BattleBots: The Tournament

Question

The results are in, the contest is over.
The winner is arshajii's EvilBot with 14 wins ahead of Neo-Bot with 13 wins and CentreBot and LastStand with 11 wins each.

Scores from the final run

Results:
java Rifter:                 9  match wins (45 total bout wins)
java EvadeBot:               10 match wins (44 total bout wins)
java EvilBot:                14 match wins (59 total bout wins)
java LastStand:              11 match wins (43 total bout wins)
java UltraBot:               9  match wins (40 total bout wins)
python ReadyAimShoot.py:     8  match wins (36 total bout wins)
./SpiralBot:                 0  match wins (1 total bout wins)
python DodgingTurret.py:     8  match wins (43 total bout wins)
ruby1.9 TroubleAndStrafe.rb: 8  match wins (41 total bout wins)
./RandomBot:                 1  match wins (6 total bout wins)
python StraightShooter.py:   8  match wins (41 total bout wins)
python mineminemine.py:      3  match wins (14 total bout wins)
./CamperBot:                 5  match wins (20 total bout wins)
python3.3 CunningPlanBot.py: 3  match wins (15 total bout wins)
node CentreBot.js:           11 match wins (44 total bout wins)
node Neo-Bot.js:             13 match wins (59 total bout wins)
python NinjaPy.py:           3  match wins (19 total bout wins)

This is a king-of-the-hill challenge. The aim is to write a bot that will beat more of the other bots than any other.

The Game

The bots will all be pitted against each other 2 at a time in a 10x10 arena with the task of reducing the opponent's energy down from 10 to 0 before its own energy is reduced to 0.

Each match will consist of 5 bouts. The winner of the match is the winner of the most bouts. The total number of match wins and bout wins will be stored by the control program and will be used to determine the overall winner of the contest. The winner receives the big green tick and the adulation of the masses.

Each bout will proceed in a number of rounds. At the beginning of each round the current state of the arena will be given to each bot and the bot will then respond with a command to determine what it wants to do next. Once both commands have been received by the control program both commands are executed at the same time and the arena and bot energy levels are updated to reflect the new state. If both bots still have enough energy to continue the game goes onto the next round. There will be a limit of 1000 rounds per bout to ensure no bout goes on forever, and in the event that this limit is reached the winner will be the bot with the most energy. If both bots have equal energy the bout is a draw and neither bot will get a point for the win (it would be as if they had both lost).

The Weapons

Each bot will have at its disposal a number of weapons:

• Armour-piercing bullets. These travel 3 squares at a time and cause 1 energy point of damage.
• Missiles. These travel 2 squares at a time and cause 3 energy points of damage at the point of impact, and 1 point of damage in all the immediately surrounding squares.
• Landmines. These are dropped in one of the squares immediately surrounding the bot and cause 2 energy points of damage when stepped on, and 1 energy point of damage to anything standing in one of the immediately surrounding squares.
• Electro-magnetic pulse. Causes both bots' movement circuits to malfunction for 2 turns, meaning they cannot move. They can, however, still deploy weapons (yes I know that's not realistic, but it's a game. It's not supposed to be real life). Edit: Each EMP deployment will cost one energy point to the bot that uses it.

Bullets/missiles can only impact with bots, or walls. They will hit any bot that is in any of the squares that they travel through. They disappear once they have hit something.

In all cases immediately surrounding squares means the 8 squares that the bot could move to on its next move - the Moore neighbourhood.

The commands

• 0 do nothing.
• N, NE, E, SE, S, SW, W, NW are all direction commands and move the bot one square in the given direction. If the bot is unable to move in that direction because there is a wall or another bot in the square, the bot remains where it is. Moving into a square that already contains a bullet or missile is safe since the bullet/missile will be considered to already be on its way out of that square.
• B followed by a space and then one of the direction commands fires an armour piercing bullet in that direction.
• M followed by a space and then one of the direction commands fires a missile in that direction.
• L followed by a space and then one of the direction commands drops a land mine on that square next to the bot. If the square is already occupied by a wall or a bot, the command is ignored. If a landmine is dropped onto another landmine, it detonates it. This will damage the bot doing the dropping, and any other bot within range of the original landmine.
• P fires the EMP.

Since only one command may be given per round, a bot can only move or fire/deploy a weapon, not do both at the same time.

Order of commands
The movement of either bot will always come first, and all movements will be attempted twice to account for another bot being in the way but moving out of the way.

Example

• Bot1 tries to move E but Bot2 is already in that square
• Control program moves on to Bot2.
• Bot2 tries to move S and succeeds because nothing is in the way.
• Bot1 gets a second attempt at doing its move. This time it succeeds and Bot1 moves E.

Once the bots have made any movements they want to make, the weapons will be fired and all projectiles (new and previously fired) will move their predefined number of squares.

The arena

At the beginning of each round the bot will receive the current state of play as the program's only command line argument:

X.....LLL.
..........
..........
..........
M.........
..........
..........
..........
..........
...B.....Y
Y 10
X 7
B 3 9 W
M 0 4 S
L 6 0
B 3 9 S
L 7 0
L 8 0

The arena comes first consisting of 10 lines of 10 characters. It is surrounded with walls which are not shown. The characters' meanings are as follows:

• . represents an empty square
• Y represents your bot.
• X represents the opponent bot.
• L represents a landmine.
• B represents a bullet in flight.
• M represents a missile in flight.

This is followed by the remaining energy of the bots, one bot per line. Only one space will separate the bot identifier from its energy level. As in the arena, Y represents your bot and X represents your opponent. Finally comes a list of the projectiles and landmines, their positions and (if appropriate) headings, again one per line.

The control program

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

#define NUMBOTS 2
#define BOUTSPERMATCH 5
#define ROUNDSPERBOUT 1000
#define MAXFILENAMESIZE 100
#define MAXWEAPONS 100
#define DISPLAYBOUTS true

typedef struct
{
  int x, y, energy;
  char cmd[5];
} Bot;

int getxmove(char cmd[5]);
int getymove(char cmd[5]);
int newposinbounds(int oldx, int oldy, int dx, int dy);
int directhit(Bot bot, int landmine[2]);
int landminecollision(int landmine1[2], int landmine2[2]);
int inshrapnelrange(Bot bot, int landmine[2]);
int directiontoint(char direction[5], char directions[8][3]);
void deployweapons(Bot *bot, Bot *enemy, int bullets[MAXWEAPONS][3], int missiles[MAXWEAPONS][3], int landmines[MAXWEAPONS][2], char directions[8][3]);
void cleararena(char arena[10][11]);

int main()
{
  FILE *fp;
  Bot b1, b2;
  int bot1, bot2, bot1bouts, bot2bouts;
  int bout, round, loop, totalprojectiles, dx, dy;
  char bots[NUMBOTS][MAXFILENAMESIZE]=
  {
    "./donowt              ",
    "php -f huggybot.php   "
  };
  char directions[8][3]={"N", "NE", "E", "SE", "S", "SW", "W", "NW"};
  char openstring[5000], argumentstring[4000], bot1string[6], bot2string[6];
  int matcheswon[NUMBOTS],boutswon[NUMBOTS];
  int missiles[MAXWEAPONS][3];
  int bullets[MAXWEAPONS][3];
  int landmines[MAXWEAPONS][2];
  int paralyzedturnsremaining=0;
  bool bot1moved;
  char arena[10][11];
  char projectiles[300][10];

  for(loop=0;loop<NUMBOTS;loop++)
  {
    matcheswon[loop]=0;
    boutswon[loop]=0;
  }

  srand(time(NULL));

  for(bot1=0;bot1<NUMBOTS-1;bot1++)
  {
    for(bot2=bot1+1;bot2<NUMBOTS;bot2++)
    {
      bot1bouts=bot2bouts=0;
      printf("%s vs %s ",bots[bot1],bots[bot2]);
      for(bout=0;bout<BOUTSPERMATCH;bout++)
      {
        printf("%d ",bout);
        //setup the arena for the bout
        b1.x=1;b1.y=1;
        b2.x=9;
        //b1.y=rand()%10;
        b2.y=rand()%10;
        b1.energy=b2.energy=10;
        //clear the previous stuff
        memset(missiles, -1, sizeof(missiles));
        memset(bullets, -1, sizeof(bullets));
        memset(landmines, -1, sizeof(landmines));
        for(round=0;round<ROUNDSPERBOUT;round++)
        {
          //draw the arena based on current state
          cleararena(arena);
          totalprojectiles=0;
          for(loop=0;loop<MAXWEAPONS;loop++)
          {
            if(bullets[loop][0]!= -1)
            {
              arena[bullets[loop][1]][bullets[loop][0]]='B';
              sprintf(projectiles[totalprojectiles], "%c %d %d %s\n", 'B', bullets[loop][0], bullets[loop][1], directions[bullets[loop][2]]);
              totalprojectiles+=1;
            }
            if(missiles[loop][0]!= -1)
            {
              arena[missiles[loop][1]][missiles[loop][0]]='M';
              sprintf(projectiles[totalprojectiles], "%c %d %d %s\n", 'M', missiles[loop][0], missiles[loop][1], directions[missiles[loop][2]]);
              totalprojectiles+=1;
            }
            if(landmines[loop][0]!= -1)
            {
              arena[landmines[loop][1]][landmines[loop][0]]='L';
              sprintf(projectiles[totalprojectiles], "%c %d %d\n", 'L', landmines[loop][0], landmines[loop][1]);
              totalprojectiles+=1;
            }
          }

          //send the arena to both bots to get the commands
          // create bot1's input
          arena[b1.y][b1.x]='Y';
          arena[b2.y][b2.x]='X';
          sprintf(bot1string, "Y %d\n", b1.energy);
          sprintf(bot2string, "X %d\n", b2.energy);
          strcpy(argumentstring, "'");
          strncat(argumentstring, *arena, 10*11);
          strcat(argumentstring, bot1string);
          strcat(argumentstring, bot2string);
          for(loop=0;loop<totalprojectiles;loop++)
          {
            strcat(argumentstring, projectiles[loop]);
          }
          strcat(argumentstring, "'");
          sprintf(openstring, "%s %s", bots[bot1], argumentstring);
          // send it and get the command back
          fp=popen(openstring, "r");
          fgets(b1.cmd, 5, fp);
          fflush(NULL);
          pclose(fp);

          // create bot2's input
          arena[b2.y][b2.x]='Y';
          arena[b1.y][b1.x]='X';
          sprintf(bot2string, "Y %d\n", b2.energy);
          sprintf(bot1string, "X %d\n", b1.energy);
          strcpy(argumentstring, "'");
          strncat(argumentstring, *arena, 10*11);
          strcat(argumentstring, bot2string);
          strcat(argumentstring, bot1string);
          for(loop=0;loop<totalprojectiles;loop++)
          {
            strcat(argumentstring, projectiles[loop]);
          }
          strcat(argumentstring, "'");
          sprintf(openstring, "%s %s", bots[bot2], argumentstring);
          // send it and get the command back
          fp=popen(openstring, "r");
          fgets(b2.cmd, 5, fp);
          fflush(NULL);
          pclose(fp);

          if(DISPLAYBOUTS)
          {
            arena[b1.y][b1.x]='A';
            arena[b2.y][b2.x]='B';
            printf("\033c");
            printf("Round: %d\n", round);
            printf("%s", arena);
            sprintf(bot1string, "A %d\n", b1.energy);
            sprintf(bot2string, "B %d\n", b2.energy);
            printf("%s%s", bot1string, bot2string);
          }

          //do bot movement phase
          if(paralyzedturnsremaining==0)
          {
            // move bot 1 first
            bot1moved=false;
            dx=dy=0;
            dx=getxmove(b1.cmd);
            dy=getymove(b1.cmd);
            if(newposinbounds(b1.x, b1.y, dx, dy))
            {
              if(!(b1.x+dx==b2.x) || !(b1.y+dy==b2.y))
              {
                bot1moved=true;
                b1.x=b1.x+dx;
                b1.y=b1.y+dy;
              }
            }
            // move bot 2 next
            dx=dy=0;
            dx=getxmove(b2.cmd);
            dy=getymove(b2.cmd);
            if(newposinbounds(b2.x, b2.y, dx, dy))
            {
              if(!(b2.x+dx==b1.x) || !(b2.y+dy==b1.y))
              {
                b2.x=b2.x+dx;
                b2.y=b2.y+dy;
              }
            }
            if(!bot1moved) // if bot2 was in the way first time, try again
            {
              dx=dy=0;
              dx=getxmove(b1.cmd);
              dy=getymove(b1.cmd);
              if(newposinbounds(b1.x, b1.y, dx, dy))
              {
                if(!(b1.x+dx==b2.x) || !(b1.y+dy==b2.y))
                {
                  b1.x=b1.x+dx;
                  b1.y=b1.y+dy;
                }
              }
            }
            //check for landmine hits
            for(loop=0;loop<MAXWEAPONS;loop++)
            {
              if(landmines[loop][0]!= -1)
              {
                if(directhit(b1, landmines[loop]))
                {
                  b1.energy-=2;
                  if(inshrapnelrange(b2, landmines[loop]))
                  {
                    b2.energy-=1;
                  }
                  landmines[loop][0]= -1;
                  landmines[loop][1]= -1;
                }
                if(directhit(b2, landmines[loop]))
                {
                  b2.energy-=2;
                  if(inshrapnelrange(b1, landmines[loop]))
                  {
                    b1.energy-=1;
                  }
                  landmines[loop][0]= -1;
                  landmines[loop][1]= -1;
                }
              }
            }
          }
          else
          {
            paralyzedturnsremaining-=1;
          }
          //do weapons firing phase
          if(strcmp(b1.cmd, "P")==0)
          {
            paralyzedturnsremaining=2;
            b1.energy--;
          }
          else if(strcmp(b2.cmd, "P")==0)
          {
            paralyzedturnsremaining=2;
            b2.energy--;
          }
          deployweapons(&b1, &b2, bullets, missiles, landmines, directions);
          deployweapons(&b2, &b1, bullets, missiles, landmines, directions);
          //do weapons movement phase
          int moves;
          for(loop=0;loop<MAXWEAPONS;loop++)
          {
            dx=dy=0;
            if(bullets[loop][0]!= -1)
            {
              dx=getxmove(directions[bullets[loop][2]]);
              dy=getymove(directions[bullets[loop][2]]);
              for(moves=0;moves<3;moves++)
              {
                if(newposinbounds(bullets[loop][0], bullets[loop][1], dx, dy))
                {
                  bullets[loop][0]+=dx;
                  bullets[loop][1]+=dy;
                  if(directhit(b1, bullets[loop]))
                  {
                    b1.energy-=1;
                    bullets[loop][0]= -1;
                    bullets[loop][1]= -1;
                    bullets[loop][2]= -1;
                  }
                  if(directhit(b2, bullets[loop]))
                  {
                    b2.energy-=1;
                    bullets[loop][0]= -1;
                    bullets[loop][1]= -1;
                    bullets[loop][2]= -1;
                  }
                }
                else
                {
                  bullets[loop][0]= -1;
                  bullets[loop][1]= -1;
                  bullets[loop][2]= -1;
                  dx=dy=0;
                }
              }
            }
          };
          for(loop=0;loop<MAXWEAPONS;loop++)
          {
            dx=dy=0;
            if(missiles[loop][0]!= -1)
            {
              dx=getxmove(directions[missiles[loop][2]]);
              dy=getymove(directions[missiles[loop][2]]);
              for(moves=0;moves<2;moves++)
              {
                if(newposinbounds(missiles[loop][0], missiles[loop][1], dx, dy))
                {
                  missiles[loop][0]+=dx;
                  missiles[loop][1]+=dy;
                  if(directhit(b1, missiles[loop]))
                  {
                    b1.energy-=3;
                    if(inshrapnelrange(b2, missiles[loop]))
                    {
                      b2.energy-=1;
                    }
                    missiles[loop][0]= -1;
                    missiles[loop][1]= -1;
                    missiles[loop][2]= -1;
                  }
                  if(directhit(b2, missiles[loop]))
                  {
                    b2.energy-=3;
                    if(inshrapnelrange(b1, missiles[loop]))
                    {
                      b1.energy-=1;
                    }
                    missiles[loop][0]= -1;
                    missiles[loop][1]= -1;
                    missiles[loop][2]= -1;
                  }
                }
                else
                {
                  if(inshrapnelrange(b1, missiles[loop]))
                  {
                    b1.energy-=1;
                  }
                  if(inshrapnelrange(b2, missiles[loop]))
                  {
                    b2.energy-=1;
                  }
                  missiles[loop][0]= -1;
                  missiles[loop][1]= -1;
                  missiles[loop][2]= -1;
                  dx=dy=0;
                }
              }
            }
          }
          //check if there's a winner
          if(b1.energy<1 || b2.energy<1)
          {
            round=ROUNDSPERBOUT;
          }
        }
        // who has won the bout
        if(b1.energy<b2.energy)
        {
          bot2bouts+=1;
          boutswon[bot2]+=1;
        }
        else if(b2.energy<b1.energy)
        {
          bot1bouts+=1;
          boutswon[bot1]+=1;
        }
      }
      if(bot1bouts>bot2bouts)
      {
        matcheswon[bot1]+=1;
      }
      else if(bot2bouts>bot1bouts)
      {
        matcheswon[bot2]+=1;
      }
      printf("\n");
    }
  }
  // output final scores
  printf("\nResults:\n");
  printf("Bot\t\t\tMatches\tBouts\n");
  for(loop=0;loop<NUMBOTS;loop++)
  {
    printf("%s\t%d\t%d\n", bots[loop], matcheswon[loop], boutswon[loop]);
  }
}

int getxmove(char cmd[5])
{
  int dx=0;
  if(strcmp(cmd, "NE")==0)
    dx= 1;
  else if(strcmp(cmd, "E")==0)
    dx= 1;
  else if(strcmp(cmd, "SE")==0)
    dx= 1;
  else if(strcmp(cmd, "SW")==0)
    dx= -1;
  else if(strcmp(cmd, "W")==0)
    dx= -1;
  else if(strcmp(cmd, "NW")==0)
    dx= -1;

  return dx;
}
int getymove(char cmd[5])
{
  int dy=0;
  if(strcmp(cmd, "N")==0)
    dy= -1;
  else if(strcmp(cmd, "NE")==0)
    dy= -1;
  else if(strcmp(cmd, "SE")==0)
    dy= 1;
  else if(strcmp(cmd, "S")==0)
    dy= 1;
  else if(strcmp(cmd, "SW")==0)
    dy= 1;
  else if(strcmp(cmd, "NW")==0)
    dy= -1;

  return dy;
}
int newposinbounds(int oldx, int oldy, int dx, int dy)
{
  return (oldx+dx>=0 && oldx+dx<10 && oldy+dy>=0 && oldy+dy<10);
}
int directhit(Bot bot, int landmine[2])
{
  return (bot.x==landmine[0] && bot.y==landmine[1]);
}
int landminecollision(int landmine1[2], int landmine2[2])
{
  return ((landmine1[1]==landmine2[1]) && abs(landmine1[0]==landmine2[0]));
}
int inshrapnelrange(Bot bot, int landmine[2])
{
  return (abs(bot.x-landmine[0])<2 && abs(bot.y-landmine[1])<2);
}
int directiontoint(char direction[5], char directions[8][3])
{
  int loop,returnval=8;
  for(loop=0;loop<8;loop++)
  {
    if(strcmp(directions[loop], direction)==0)
      returnval=loop;
  }
  return returnval;
}
void deployweapons(Bot *bot, Bot *enemy, int bullets[MAXWEAPONS][3], int missiles[MAXWEAPONS][3], int landmines[MAXWEAPONS][2], char directions[8][3])
{
  int loop;
  if(strlen(bot->cmd)>2)
  {
    if(bot->cmd[0]=='B')
    {
      int weaponslot=0;
      while(bullets[weaponslot][0]!= -1)
        weaponslot+=1;
      bullets[weaponslot][0]=bot->x;
      bullets[weaponslot][1]=bot->y;
      bullets[weaponslot][2]=directiontoint(bot->cmd+2, directions);
      if(bullets[weaponslot][2]>7)
      {
        // direction wasn't recognized so clear the weapon
        bullets[weaponslot][0]= -1;
        bullets[weaponslot][1]= -1;
        bullets[weaponslot][2]= -1;
      }
    }
    if(bot->cmd[0]=='M')
    {
      int weaponslot=0;
      while(missiles[weaponslot][0]!= -1)
        weaponslot+=1;
      missiles[weaponslot][0]=bot->x;
      missiles[weaponslot][1]=bot->y;
      missiles[weaponslot][2]=directiontoint(bot->cmd+2, directions);
      if(missiles[weaponslot][2]>7)
      {
        // direction wasn't recognized so clear the weapon
        missiles[weaponslot][0]= -1;
        missiles[weaponslot][1]= -1;
        missiles[weaponslot][2]= -1;
      }
    }
    if(bot->cmd[0]=='L')
    {
      int weaponslot=0;
      while(landmines[weaponslot][0]!= -1)
        weaponslot+=1;
      if(newposinbounds(bot->x, bot->y, getxmove(bot->cmd+2), getymove(bot->cmd+2)))
      {
        landmines[weaponslot][0]=bot->x+getxmove(bot->cmd+2);
        landmines[weaponslot][1]=bot->y+getymove(bot->cmd+2);

        //check for landmine hits
        for(loop=0;loop<MAXWEAPONS;loop++)
        {
          if(landmines[loop][0]!= -1)
          {
            if(landminecollision(landmines[weaponslot], landmines[loop]) && weaponslot!=loop)
            {
              if(inshrapnelrange(*bot, landmines[loop]))
              {
                bot->energy-=1;
              }
              if(inshrapnelrange(*enemy, landmines[loop]))
              {
                enemy->energy-=1;
              }
              landmines[loop][0]= -1;
              landmines[loop][1]= -1;
              landmines[weaponslot][0]= -1;
              landmines[weaponslot][1]= -1;
            }
          }
        }
      }
    }
  }
}
void cleararena(char arena[10][11])
{
  int loop;
  memset(arena, '.', 110);
  for(loop=0;loop<10;loop++)
  {
    arena[loop][10]='\n';
  }
}

The control program will call your bot from the command line. For this reason, programs which cannot be called from the command line will be considered invalid. I apologise to those whose language of choice doesn't work that way, but doing each match manually would be impractical.

intx13 has kindly written a more robust version of the control program with some bugfixes which you can find here.

Suggestions for improvements or bug-fixes to the control program are welcome.

Test bots

None of the test bots will be included in the scoring runs. They're just for testing purposes.

Dudley DoNowt (C)

int main(int argc, char *argv)
{
  printf("0");
}

Does nothing regardless of the situation. Not expected to win much.

HuggyBot (PHP)

<?php
$arena=$argv[1];
list($meX, $meY)=findMe($arena);
list($oppX, $oppY)=findOpp($arena);
if($meY<$oppY)
{
  if($meX<$oppX)
    echo "SE";
  elseif($meX==$oppX)
    echo "S";
  else
    echo "SW";
}
elseif($meY==$oppY)
{
  if($meX<$oppX)
    echo "E";
  else
    echo "W";
}
else
{
  if($meX<$oppX)
    echo "NE";
  elseif($meX==$oppX)
    echo "N";
  else
    echo "NW";
}

function findMe($arena)
{
  return find("Y", explode("\n", $arena));
}

function findOpp($arena)
{
  return find("X", explode("\n", $arena));
}

function find($char, $array)
{
  $x=0;
  $y=0;
  for($loop=0;$loop<10;$loop++)
  {
    if(strpos($array[$loop], $char)!==FALSE)
    {
      $x=strpos($array[$loop], $char);
      $y=$loop;
    }
  }
  return array($x, $y);
}
?>

Tries to get right next to the opponent. Vulnerable to landmines since it doesn't look for them. Makes firing missiles a less effective tactic for the opponent when it achieves its goal.

The results

The final scoring run will be done after 23:59 on the 24th March 2014. I will run test runs regularly so that entrants can see how their bots are stacking up against the current opposition.

Entries

Entries should include your bot's source, and the command line argument I'll need to use to run it. You're welcome to post as many different entries as you like, but each answer should contain only one bot.

Important

It seems that some entries want to write to disk to retain some state between runs. These are new rules regarding writing to disk.

• You may modify the source of your own bot. Modifying any other bot is cheating and will result in the offending bot being disqualified.
• You may write to a file created for the purpose of storing state. This file must be stored in a subdirectory of the directory where your bot is located. The subdirectory will be named state. Writing to any other part of the filesystem (other than your own source) is disallowed.

Answer 1

EvilBot

^{a bot that tries to be as evil as possible}

Well here's what I've got: a Java bot that tries to get as close to the opponent a circular strip of radius 2.5 around the center of the arena as possible and then do as much damage as it can when it can. Its movement pattern is based on assigning a "danger" value to each of its neighboring squares, and deciding to move based on these values and based on a tendency to be as close to a circular region of radius 2.5 about the center of the arena. I used some of the nuts and bolts from @Geobits's answer (e.g. having an abstract BattleBot class and the parsing technique), so thanks! I'm probably going to modify/expand what I have so far, although it does fare quite well as is with the other bots posted so far. The code is below. (if anyone else is using Java, feel free to use my abstract/helper classes.)

(EvilBot.java)

import java.io.File; // debugging
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner; // debugging

class Point {

    private int x, y;

    public Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    public int distTo(Point other) {
        return Math.max(Math.abs(x - other.x), Math.abs(y - other.y));
    }

    public double conventionalDistTo(Point other) {
        return Math.hypot(x - other.x, y - other.y);
    }

    @Override
    public boolean equals(Object other) {
        if (!(other instanceof Point))
            return false;

        Point otherPoint = (Point) other;

        return x == otherPoint.x && y == otherPoint.y;
    }

    @Override
    public int hashCode() {
        return x * (1 << Arena.ARENA_SIZE) + y;
    }

    @Override
    public String toString() {
        return "(" + x + "," + y + ")";
    }
}

interface ArenaElement {
    char getSymbol();
}

enum Projectile implements ArenaElement {

    BULLET('B', 3, 1) {

    },

    MISSILE('M', 2, 3) {

    },

    LANDMINE('L', 0, 2) {
        @Override
        public int timeUntilImpact(Point current, Point target, Direction dir) {
            return current.equals(target) ? 0 : -1;
        }
    };

    private final char symbol;
    private final int speed;
    private final int damage;

    private Projectile(char symbol, int speed, int damage) {
        this.symbol = symbol;
        this.speed = speed;
        this.damage = damage;
    }

    @Override
    public char getSymbol() {
        return symbol;
    }

    public int getSpeed() {
        return speed;
    }

    public int getDamage() {
        return damage;
    }

    public static Projectile fromSymbol(char symbol) {
        for (Projectile p : values()) {
            if (p.getSymbol() == symbol)
                return p;
        }

        return null;
    }

    public int timeUntilImpact(Point current, Point target, Direction dir) {

        final int dx = target.getX() - current.getX();
        final int dy = target.getY() - current.getY();

        if (!(dx == 0 || dy == 0 || dx == dy || dx == -dy))
            return -1;

        if (dx == 0) {
            if (dy > 0 && dir != Direction.N)
                return -1;

            if (dy < 0 && dir != Direction.S)
                return -1;
        }
        if (dy == 0) {
            if (dx > 0 && dir != Direction.E)
                return -1;

            if (dx < 0 && dir != Direction.W)
                return -1;
        }
        if (dx == dy) {
            if (dx > 0 && dir != Direction.NE)
                return -1;

            if (dx < 0 && dir != Direction.SW)
                return -1;
        }
        if (dx == -dy) {
            if (dx > 0 && dir != Direction.SE)
                return -1;

            if (dx < 0 && dir != Direction.NW)
                return -1;
        }

        int dist = target.distTo(current);

        return (dist / speed) + (dist % speed == 0 ? 0 : 1);
    }
}

enum BotType implements ArenaElement {

    ME('Y'), ENEMY('X');

    private final char symbol;

    private BotType(char symbol) {
        this.symbol = symbol;
    }

    @Override
    public char getSymbol() {
        return symbol;
    }

    public static BotType fromSymbol(char symbol) {
        for (BotType bt : values()) {
            if (bt.getSymbol() == symbol)
                return bt;
        }

        return null;
    }
}

enum EmptySpot implements ArenaElement {

    EMPTY;

    @Override
    public char getSymbol() {
        return '.';
    }

    public static EmptySpot fromSymbol(char symbol) {
        for (EmptySpot es : values()) {
            if (es.getSymbol() == symbol)
                return es;
        }

        return null;
    }
}

enum Direction {
    N, NE, E, SE, S, SW, W, NW
}

class Arena {

    public static final int ARENA_SIZE = 10;
    public static final Point center = new Point(ARENA_SIZE / 2, ARENA_SIZE / 2);

    private ArenaElement[][] arena;

    private Arena(boolean fill) {
        arena = new ArenaElement[ARENA_SIZE][ARENA_SIZE];

        if (!fill)
            return;

        for (int i = 0; i < ARENA_SIZE; i++) {
            for (int j = 0; j < ARENA_SIZE; j++) {
                arena[i][j] = EmptySpot.EMPTY;
            }
        }
    }

    public boolean inBounds(int x, int y) {
        return x >= 0 && x < ARENA_SIZE && y >= 0 && y < ARENA_SIZE;
    }

    public boolean inBounds(Point p) {
        final int x = p.getX(), y = p.getY();
        return inBounds(x, y);
    }

    public ArenaElement get(int x, int y) {
        if (!inBounds(x, y)) {
            return null; // be cautious of this
        }

        return arena[ARENA_SIZE - 1 - y][x];
    }

    public ArenaElement get(Point p) {
        return get(p.getX(), p.getY());
    }

    // note: a point is considered its own neighbor
    public List<Point> neighbors(Point p) {
        List<Point> neighbors = new ArrayList<Point>(9);

        for (int i = -1; i <= 1; i++) {
            for (int j = -1; j <= 1; j++) {
                Point p1 = new Point(p.getX() + i, p.getY() + j);

                if (get(p1) != null)
                    neighbors.add(p1);
            }
        }

        return neighbors;
    }

    public Point findMe() {
        for (int i = 0; i < ARENA_SIZE; i++) {
            for (int j = 0; j < ARENA_SIZE; j++) {
                if (get(i, j) == BotType.ME)
                    return new Point(i, j);
            }
        }

        return null;
    }

    public Point findEnemy() {
        for (int i = 0; i < ARENA_SIZE; i++) {
            for (int j = 0; j < ARENA_SIZE; j++) {
                if (get(i, j) == BotType.ENEMY)
                    return new Point(i, j);
            }
        }

        return null;
    }

    public Point impactOfRayFromPointInDirection(Point p, Direction dir) {
        int x = p.getX(), y = p.getY();

        switch (dir) {
        case N:
            y += (Arena.ARENA_SIZE - 1 - y);
            break;
        case NE: {
            int dx = (Arena.ARENA_SIZE - 1 - x);
            int dy = (Arena.ARENA_SIZE - 1 - y);

            int off = Math.max(dx, dy);

            x += off;
            y += off;
            break;
        }
        case E:
            x += (Arena.ARENA_SIZE - 1 - x);
            break;
        case SE: {
            int dx = (Arena.ARENA_SIZE - 1 - x);
            int dy = y;

            int off = Math.max(dx, dy);

            x += off;
            y -= off;
            break;
        }
        case S:
            y = 0;
            break;
        case SW: {
            int dx = x;
            int dy = y;

            int off = Math.max(dx, dy);

            x -= off;
            y -= off;
            break;
        }
        case W:
            x = 0;
            break;
        case NW: {
            int dx = x;
            int dy = (Arena.ARENA_SIZE - 1 - y);

            int off = Math.max(dx, dy);

            x -= off;
            y += off;
            break;
        }
        }

        return new Point(x, y);
    }

    private static ArenaElement fromSymbol(char symbol) {
        ArenaElement e = EmptySpot.fromSymbol(symbol);

        if (e != null)
            return e;

        e = Projectile.fromSymbol(symbol);

        if (e != null)
            return e;

        return BotType.fromSymbol(symbol);
    }

    public static Arena parse(String[] input) {
        Arena arena = new Arena(false);

        for (int i = 0; i < ARENA_SIZE; i++) {
            for (int j = 0; j < ARENA_SIZE; j++) {
                char symbol = input[i].charAt(j);

                arena.arena[i][j] = fromSymbol(symbol);
            }
        }

        return arena;
    }
}

abstract class BaseBot {

    protected static class ProjectileInfo {
        Projectile projectile;
        Point position;
        Direction direction;

        @Override
        public String toString() {
            return projectile.toString() + " " + position + " " + direction;
        }
    }

    protected Arena arena;

    protected Point myPos;
    protected int energy;

    protected Point enemyPos;
    protected int enemyEnergy;

    public List<ProjectileInfo> projectiles;

    public BaseBot(String[] args) {
        if (args.length < 1)
            return;

        String[] lines = args[0].split("\r?\n");

        projectiles = new ArrayList<ProjectileInfo>(lines.length
                - Arena.ARENA_SIZE - 2);

        arena = Arena.parse(lines);
        myPos = arena.findMe();
        enemyPos = arena.findEnemy();

        for (int i = Arena.ARENA_SIZE; i < lines.length; i++) {
            parseInputLine(lines[i]);
        }
    }

    private void parseInputLine(String line) {
        String[] split = line.split(" ");

        char c0 = line.charAt(0);
        if (c0 == 'Y') {
            energy = Integer.parseInt(split[1]);
        } else if (c0 == 'X') {
            enemyEnergy = Integer.parseInt(split[1]);
        } else {
            ProjectileInfo pinfo = new ProjectileInfo();
            pinfo.projectile = Projectile.fromSymbol(split[0].charAt(0));
            pinfo.position = new Point(Integer.parseInt(split[1]),
                    Arena.ARENA_SIZE - 1 - Integer.parseInt(split[2]));

            if (split.length > 3)
                pinfo.direction = Direction.valueOf(split[3]);

            projectiles.add(pinfo);
        }
    }

    abstract String getMove();
}

public class EvilBot extends BaseBot {

    public static final boolean DEBUG = false;

    public static void main(String... args) throws Exception {
        if (DEBUG) {
            StringBuffer input = new StringBuffer();
            Scanner scan = new Scanner(new File("a.txt"));

            while (scan.hasNextLine()) {
                input.append(scan.nextLine());
                input.append('\n');
            }

            scan.close();

            args = new String[] { input.toString() };
        }

        System.out.print(new EvilBot(args).getMove());
    }

    public EvilBot(String[] args) {
        super(args);
    }

    /*
     * Direction to p if perfectly aligned, null otherwise
     */
    private Direction getDirTo(Point p) {

        final int dx = p.getX() - myPos.getX();
        final int dy = p.getY() - myPos.getY();

        if (dx == 0) {
            return (dy > 0) ? Direction.N : Direction.S;
        }
        if (dy == 0) {
            return (dx > 0) ? Direction.E : Direction.W;
        }
        if (dx == dy) {
            return (dy > 0) ? Direction.NE : Direction.SW;
        }
        if (dx == -dy) {
            return (dy > 0) ? Direction.NW : Direction.SE;
        }

        return null;
    }

    /*
     * Direction towards p (best approximation)
     */
    private Direction getDirTowards(Point p) {
        Direction minDir = null;
        double minDist = 0;

        for (Direction dir : Direction.values()) {
            double dist = arena.impactOfRayFromPointInDirection(myPos, dir)
                    .conventionalDistTo(p);

            if (minDir == null || dist < minDist) {
                minDir = dir;
                minDist = dist;
            }
        }

        return minDir;
    }

    private boolean isEnemyCloseToWall() {
        return (enemyPos.getX() < 2 || enemyPos.getY() < 2
                || enemyPos.getX() > Arena.ARENA_SIZE - 3 || enemyPos.getY() > Arena.ARENA_SIZE - 3);
    }

    private String missileAttack() {
        return "M " + getDirTowards(enemyPos);
    }

    @Override
    public String getMove() {
        List<Point> neighbors = arena.neighbors(myPos);

        Map<Point, Double> dangerFactors = new HashMap<Point, Double>();

        for (Point neighbor : neighbors) {

            double dangerFactor = 0;

            if (arena.get(neighbor) == Projectile.LANDMINE) {
                dangerFactor += 2;
            }

            for (ProjectileInfo pi : projectiles) {

                int time = pi.projectile.timeUntilImpact(pi.position, neighbor,
                        pi.direction);

                if (time > 0) {
                    dangerFactor += ((double) pi.projectile.getDamage()) / time;
                }
            }

            dangerFactors.put(neighbor, dangerFactor);
        }

        if (dangerFactors.get(myPos) == 0) {
            // we are safe for now...

            Direction dir = getDirTo(enemyPos);
            boolean closeToWall = isEnemyCloseToWall();

            if (dir != null) {
                int dist = myPos.distTo(enemyPos);

                if (dist < Projectile.MISSILE.getSpeed() * 2) {
                    return "M " + dir;
                } else {
                    return "B " + dir;
                }
            } else if (closeToWall) {

                if (Math.random() > 0.5) // so we don't get caught in loops
                    return missileAttack();
            }
        }

        // move!
        double leastDanger = Double.POSITIVE_INFINITY;

        for (Entry<Point, Double> entry : dangerFactors.entrySet()) {
            if (entry.getValue() < leastDanger)
                leastDanger = entry.getValue();
        }

        Point moveTo = null;

        for (Entry<Point, Double> entry : dangerFactors.entrySet()) {
            if (entry.getKey().equals(myPos))
                continue;

            if (entry.getValue() == leastDanger) {

                double d1 = entry.getKey().conventionalDistTo(Arena.center);
                double d2 = moveTo == null ? 0 : moveTo
                        .conventionalDistTo(Arena.center);

                if (moveTo == null || Math.abs(d1 - 2.5) < Math.abs(d2 - 2.5)) {

                    moveTo = entry.getKey();
                }
            }
        }

        if (moveTo == null) {
            return missileAttack();
        }

        return getDirTo(moveTo).toString();
    }
}

Usage:

javac EvilBot.java
java EvilBot <input>

---

Notes:

• Currently, land mines are not being used, only dodged. I'm probably not going to change this, since using land mines appears to do more harm than good (at least for EvilBot) judging by a few tests I ran.

• Currently, EMP is not being used. I tried the strategy of aligning with the opponent and firing the EMP followed by missiles, but there are a few counter-strategies to this that would win almost 100% of the time, so I decided to abandon that route. I might explore using the EMP in different ways later on.

Answer 2

Rifter

This bot takes different actions based on what bot it's fighting. To determine the opponent, it flips its own state and feeds it into the other bots to see what they would do, and compares that to what they actually do. Once they hit a threshold of 'correct' moves, it stops testing the others.

Once it knows what bot it's fighting, it generally knows where it will be on the next turn, so it can fire there instead of their current position.

Of course, there are some drawbacks. One is that bots that have "random" activity aren't detected so well. This is balanced by using the King's Last Stand logic when the opponent isn't known.

However, if a bot is purely deterministic, this has no trouble figuring out who it is. It can then be easily adapted to the situation by adding more cases into its logic for each opponent. For example, fighting Last Stand, it will corner him, stand 2x1 away so that the he can't move or fire directly, and shoot missiles into the wall behind, killing it with splash damage.

Like my others, it extends BattleBot.java:

import java.awt.Point;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Rifter extends BattleBot{

    String output="0";
    String state;
    String oldState = null;
    List<Rift> rifts;
    Rift chosen;
    List<Point> safe;
    Point probable;
    int round;

    final int testCount = 100;

    Rifter(String[] args) {
        super(args.length>0?args:testState);
        state = args.length>0?args[0]:testState[0];
        round = 0;
    }

    public static void main(String[] args) {
        debug = false;
        System.out.print(new Rifter(args).execute());
    }

    @Override
    String execute() {
        if(!valid)
            return "0";
        init();
        probable = getLikelyPosition();
        if(!safe.contains(yPosition) && evade())
            return output;
        if(riftShift())
            return output;
        return fallback();
    }

    boolean riftShift(){
        if(chosen==null)
            return false;
        if("P".equals(chosen.nextAction))
            return fireAt(xPosition, true);
        switch(getChosenIndex()){
        case 1:
            output = fightStand();
            break;
        case 2:
            output = fightEvil();
            break;
        default:
            output = fallback();
        }
        return output.equals("0")?false:true;
    }

    int getChosenIndex(){
        for(int i=0;i<baseBots.length;i++)
            if(chosen.bot.equals(baseBots[i]))
                return i;
        return -1;
    }

    int distanceToWall(Point pos){
        int min = Math.min(pos.x,  pos.y);
        min = Math.min(min, (arenaSize - 1) - pos.x);
        return Math.min(min, (arenaSize - 1) - pos.y);
    }

    String fightStand(){
        int wall = distanceToWall(xPosition);
        if(wall > 0 || distance(yPosition, probable) > 2){
            if(moveToward(probable, NONE))
                return output;
            if(fireAt(probable, false))
                return output;
        }

        if(probable.x==0 && probable.y==0)
            return "M NW";
        if(probable.x==arenaSize-1 && probable.y==0)
            return "M NE";
        if(probable.x==arenaSize-1 && probable.y == arenaSize-1)
            return "M SE";
        if(probable.x==0 && probable.y == arenaSize-1)
            return "M SW";
        if(probable.x==0)
            return "M W";
        if(probable.x==arenaSize-1)
            return "M E";
        if(probable.y==0)
            return "M N";
        if(probable.y==arenaSize-1)
            return "M S";

        return "M " + headings[headingToPoint(probable)];
    }

    String fightEvil(){
        if(areAligned(yPosition,xPosition)){
            if(distance(yPosition,xPosition)>3)
                if(moveToward(probable,UNALIGN))
                    return output;
            if(fireAt(probable, false))
                return output;
        }
        if(fireAt(probable, false))
            return output;
        if(moveToward(center, ALIGN))
            return output;
        return "0";
    }

    String fallback(){
        output = getOutputFrom(fallbackBots[rand.nextInt(fallbackBots.length)]);
        if(output==null)
            output="0";
        return output;
    }

    int NONE = 0;
    int ALIGN = 1;
    int UNALIGN = 2;

    boolean moveToward(Point target, int align){
        Point closest = new Point(-99,-99);
        for(Point pos : safe){
            if(pos.equals(yPosition))
                continue;
            if(distance(pos,target) < distance(closest,target)){
                if(areAligned(pos,target) && align == UNALIGN)
                    continue;
                if(!areAligned(pos,target) && align == ALIGN)
                    continue;
                closest = pos;
            }
        }

        if(isOutside(closest))
            for(Point pos : safe)
                    if(distance(pos,target) < distance(closest,target))
                        closest = pos;      
        if(distance(closest,target) > distance(yPosition,target))
            return false;
        output = headings[headingToPoint(closest)];
        return true;
    }

    boolean fireAt(Point target, boolean override){
        if(!override && !areAligned(yPosition, target))
            return false;
        int dist = distance(yPosition, target);
        if(!override && dist>3)
            return false;
        int heading = headingToPoint(target);
        output = "M ";
        if(dist > 3 || dist == 1)
            output = "B ";
        output += headings[heading];
        return true;
    }

    String getOutputFrom(String bot){
        return new Rift(bot,0).foretell(state);
    }

    boolean evade(){
        if(safe.isEmpty())
            return false;
        Point dest = null;
        for(Point pos : safe)
            if(areAligned(pos,probable))
                dest = pos;
        if(dest==null){
            output = getOutputFrom("java LastStand");
            return true;
        }
        output = headings[headingToPoint(dest)];
        return true;
    }

    Point getLikelyPosition(){
        if(chosen!=null)
            return chosen.getNextPosition(null);
        if(round > testCount)
            return xPosition;

        int[] arena = new int[arenaSize*arenaSize];
        for(Rift rift : rifts){
            Point next = rift.getNextPosition(null);
            if(!isOutside(next))
                arena[next.y*arenaSize+next.x]++;
        }
        int max = 0, index = -1;
        for(int i=0;i<arena.length;i++){
            if(arena[i] > max){
                max = arena[i];
                index = i;
            }
        }
        Point dest = new Point(index%arenaSize, index/arenaSize);
        return isOutside(dest)?xPosition:dest;
    }

    boolean areAligned(Point a, Point b){
        int x = Math.abs(a.x - b.x);
        int y = Math.abs(a.y - b.y);
        if(x==0 || y==0 || x==y)
            return true;
        return false;
    }

    void init(){
        safe = new ArrayList<Point>();
        if(spotCollision(yPosition)==null)
            safe.add(yPosition);

        for(int heading=0;heading<8;heading++){
            Point pos = nextPosition(heading, yPosition);
            if(isOutside(pos))
                continue;
            if(spotCollision(pos)==null)
                safe.add(pos);
        }

        loadBots(readState());
        updateRifts();
        writeState();
    }

    void updateRifts(){
        if(chosen == null && round < testCount)
            for(Rift rift : rifts)
                if(rift.validate(oldState))
                    rift.correct++;
    }

    Rift chooseBot(){
        double avg = 0.0;
        int highest = 0;
        Rift choice = null;

        for(Rift rift : rifts){
            avg += rift.correct;
            if(rift.correct >= highest){
                highest = rift.correct;
                choice = rift;
            }
        }
        avg /= rifts.size();
        if(choice!= null && (choice.correct > 8) && choice.correct > avg*2)
            return choice;
        else
            return null;
    }

    boolean writeState(){
        File dir = new File("state");
        dir.mkdirs();
        File file = new File("state/rifter.state");
        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter(file));
            writer.write(">" + round + "\n");
            for(Rift rift : rifts)
                writer.write(":" + rift.correct + "|" + rift.bot + "\n");
            writer.write(state);
            writer.flush();
            writer.close();
        } catch (IOException e) {
            log(e.getMessage());
            return false;
        }
        return true;
    }

    List<String> readState(){
        List<String> bots = new ArrayList<String>();
        File file = new File("state/rifter.state");
        if(file.exists()){
            try {
                BufferedReader reader = new BufferedReader(new FileReader(file));
                String line;
                String oldState = "";
                line = reader.readLine();
                if(line != null && line.startsWith(">"))
                    round = Integer.valueOf(line.substring(1)) + 1;
                while((line = reader.readLine()) != null){
                    if(line.startsWith(":"))
                        bots.add(line.substring(1));
                    else 
                        oldState += line + "\n";                                            
                }
                reader.close();
                BattleBot bot = new Rifter(new String[]{oldState});
                if(isStateInvalid(bot)){
                    bots.clear();
                    oldState = "";
                    round = 0;
                }
                this.oldState = oldState;
            } catch(Exception e){
                log(e.getMessage());
                bots.clear();
                this.oldState = "";
            }
        }
        return bots.isEmpty()?Arrays.asList(baseBots):bots;
    }

    boolean isStateInvalid(BattleBot bot){
        if(!bot.valid)
            return true;
        if(distance(bot.xPosition, xPosition) > 1)
            return true;
        if(distance(bot.yPosition, yPosition) > 1)
            return true;
        if(xEnergy > bot.xEnergy || yEnergy > bot.yEnergy)
            return true;
        return false;
    }

    List<Rift> loadBots(List<String> bots){
        rifts = new ArrayList<Rift>();
        String flipped = flipState(state);
        for(String bot : bots){
            String[] tokens = bot.split("\\|");
            Rift rift;
            if(tokens.length < 2)
                rift = new Rift(bot, 0);
            else
                rift = new Rift(tokens[1], Integer.valueOf(tokens[0]));         
            rifts.add(rift);
        }
        if((chosen = chooseBot()) == null)
            if(round < testCount)
                for(Rift rift : rifts)
                    rift.nextAction = rift.foretell(flipped);
        else
            chosen.nextAction = chosen.foretell(flipped);

        return rifts;
    }

    String flipState(String in){
        String tmp = in.replaceAll("X", "Q");
        tmp = tmp.replaceAll("Y", "X");
        tmp = tmp.replaceAll("Q", "Y");
        String[] lines = tmp.split("\\r?\\n");
        tmp = lines[arenaSize];
        lines[arenaSize] = lines[arenaSize+1];
        lines[arenaSize+1] = tmp;
        String out = "";
        for(int i=0;i<lines.length;i++)
            out += lines[i] + "\n";
        return out.trim();
    }

    class Rift{
        String bot;
        String nextAction;
        String state;
        String nextState;
        int correct;

        Rift(String name, int count){
            bot = name;
            correct = count;
        }

        Point getNextPosition(String action){
            if(action==null)
                action = nextAction;
            if(action==null || action.length()<1)
                return xPosition;
            int heading = getHeading(action.split(" ")[0]);
            return nextPosition(heading, xPosition);
        }

        boolean validate(String oldState){
            boolean valid = true;
            if(oldState == null)
                return valid;
            if(oldState.split("\\r?\\n").length < 12)
                return valid;
            String action = foretell(flipState(oldState));
            if(action==null || action.length() < 1){
                log(this.bot + " : " + "invalid action");
                return valid;
            }
            BattleBot bot = new Rifter(new String[]{oldState});
            switch(action.charAt(0)){
            case 'B':
            case 'M':
            case 'L':
                valid = testShot(action, bot);
                break;
            case 'P':
            case '0':
                valid = testNothing(bot);
                break;
            default:
                valid = testMovement(action, bot);
                break;
            }
            log(this.bot + " : " + action + " : " + valid); 

            return valid;
        }

        boolean testNothing(BattleBot bot){
            if(!xPosition.equals(bot.xPosition))
                return false;
            for(Weapon weapon : weapons){
                int dist = weapon.type==LANDMINE?1:weapon.speed;
                log(dist);
                if(distance(weapon.position, bot.xPosition) != dist)
                    continue;
                int dir = weapon.heading;
                if(isHeadingExact(dir,bot.xPosition,weapon.position))
                    return false;
            }
            return true;
        }

        boolean testShot(String act, BattleBot bot){
            if(!xPosition.equals(bot.xPosition))
                return false;
            if(weapons == null)
                return false;
            String[] tokens = act.split(" ");
            char which = tokens[0].charAt(0);
            int type = which=='B'?BULLET:
                   which=='M'?MISSILE:
                              LANDMINE;

            for(Weapon weapon : weapons){
                if(weapon.type != type)
                    continue;
                int dist = weapon.type==LANDMINE?1:weapon.speed;
                log(dist);
                if(distance(weapon.position, bot.xPosition) != dist)
                    continue;
                int dir;
                if(act==null)
                    dir = weapon.heading;
                else if(tokens.length < 2)
                    return false;
                else
                    dir = getHeading(tokens[1]);
                if(isHeadingExact(dir,bot.xPosition,weapon.position))
                    return true;
            }
            return false;

        }

        boolean testMovement(String act, BattleBot bot){
            return xPosition.equals(nextPosition(getHeading(act), bot.xPosition));
        }

        String foretell(String state){
            this.state = state;
            String[] cmdRaw = bot.split(" ");
            String[] cmd = new String[cmdRaw.length+1];
            for(int i=0;i<cmdRaw.length;i++)
                cmd[i] = cmdRaw[i];
            cmd[cmd.length-1]=state;

            String out = null;
            try {
                Process p = Runtime.getRuntime().exec(cmd);
                p.waitFor();
                BufferedReader err = new BufferedReader(new InputStreamReader(p.getErrorStream()));
                String line;
                while((line = err.readLine()) != null){
                    out = line;
                }
                err.close();
                BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
                while((line = reader.readLine()) != null){
                    out = line;
                }
                reader.close();
            } catch (Exception e) {
                log(e.getMessage());
            }
            return out!=null&&out.length()<6&&out.length()>0?out:null;
        }
    }   

    String fallbackBots[] = {"node Neo-Bot.js"};

    String[] baseBots =     {
                             "java EvadeBot", 
                             "java LastStand",
                             "java EvilBot",
                             "python ReadyAimShoot.py",
                             "python DodgingTurret.py",
                             "python mineminemine.py",
                             "python StraightShooter.py",
                             "./RandomBot",
                             "./SpiralBot",
                             "ruby1.9 TroubleAndStrafe.rb",
                             "python3 CunningPlanBot.py",
                             "./CamperBot",
                             "node CentreBot.js",
                             "node Neo-Bot.js",
                             "java UltraBot",
                             "python NinjaPy.py"
    };

    static String[] testState = {".X....LLL.\n..........\n.M........\n..........\nM.........\n..........\n..........\n..........\n.Y........\n...B......\nY 10\nX 7\nM 1 2 S"};
}

Answer 3

ReadyAimShoot

a R Bot

input <- strsplit(commandArgs(TRUE),split="\\\\n")[[1]]
arena <- do.call(rbind,strsplit(input[1:10],"")) #Parse arena
life <- as.integer(strsplit(input[11:12]," ")[[1]][2]) #Parse stats
stuff <- strsplit(input[13:length(input)]," ") #Parse elements
if(length(input)>12){ #What are they
    stuff <- strsplit(input[13:length(input)]," ")
    whatstuff <- sapply(stuff,`[`,1)
    }else{whatstuff<-""}
if(sum(whatstuff=="L")>1){ #Where are the mines
    mines <- t(apply(do.call(rbind,stuff[whatstuff=="L"])[,3:2],1,as.integer))+1
    }else if(sum(whatstuff=="L")==1){
        mines <- as.integer(stuff[whatstuff=="L"][[1]][3:2])+1
    }else{mines <- c()}
me <- which(arena=="Y",arr.ind=T) #Where am I
other <- which(arena=="X",arr.ind=T) #Where is the target
direction <- other-me #Direction of the other bot in term of indices
if(length(mines)>2){ #Direction of mines in term of indices
    dirmines <- mines-matrix(rep(me,nrow(mines)),nc=2,byrow=T)
    }else if(length(mines)==1){
        dirmines <- mines-me
        }else{dirmines<-c()}
file <- normalizePath(gsub("^--file=","",grep("^--file=",commandArgs(FALSE),v=TRUE))) #Path to this very file
f1 <- readLines(file) #Read-in this source file
where <- function(D){ #Computes direction of something in term of NSWE
    d <- ""
    if(D[2]<0) d <- paste(d,"W",sep="")
    if(D[2]>0) d <- paste(d,"E",sep="")
    if(D[1]<0) d <- paste(d,"N",sep="")
    if(D[1]>0) d <- paste(d,"S",sep="")
    d
    }
d <- where(direction) #Direction of the other bot in term of NSWE
M <- dirmines[dirmines[,1]%in%(-1:1) & dirmines[,2]%in%(-1:1),] #Which mines are next to me
if(length(M)>2){m<-apply(M,1,where)}else if(length(M)==1){m<-where(M)}else{m<-""} #Direction of close-by mines in term of NSWE
if(any(direction==0) & life >1 & !grepl("#p_fired", tail(f1,1))){
    # If aligned with target, if life is more than one 
    # and if this source file doesn't end with a comment saying the EMP was already fired
    # Fire the EMP, and leave comment on this file saying so
    action <- "P"
    f2 <- c(f1,"#p_fired2")
    cat(f2, file=file, sep="\n")
    }else if(tail(f1,1)=="#p_fired2"){
    # If EMP have been fired last turn
    # Send missile in direction of target
    # Change comment on file.
    action <- paste("M", d)
    f2 <- c(f1[-length(f1)], "#p_fired1")
    cat(f2, file=file, sep="\n")
    }else if(tail(f1,1)=="#p_fired1"){
    # If EMP was fired two turns ago
    # Send bullet and erase comment line.
    action <- paste("B", d)
    f2 <- f1[-length(f1)]
    cat(f2, file=file, sep="\n")
    }
if (any(direction==0) & life<2){
    # If aligned but life is 1 don't fire the EMP, but send missile instead
    action <- paste("M",d)
    }
if (!any(direction==0)){
    # If not aligned, try to align using shortest, landmine-free direction
    if(direction[2]<direction[1]){
        if(grepl('W',d) & !'W'%in%m){action <- 'W'}
        if(grepl('E',d) & !'E'%in%m){action <- 'E'}
        }else if(direction[2]>=direction[1]){
            if(grepl('N',d) & !'N'%in%m){action <- 'N'}
            if(grepl('S',d) & !'S'%in%m){action <- 'S'}
            }else{ #If no landmine-free direction, don't move
                action <- 0
                }
    }
cat(action,"\n")

This bot tries to place itself in the same row or column as the target, when it is aligned with the target it fires the EMP, then on the following turn it fires a missile toward the target, and then a bullet. It should also be aware of the surrounding mine and avoid them but is completely oblivious of bullets and missiles. If life is already at 1 it skips the EMP.
To keep track of when it triggers the EMP, it modifies its source code by adding a comment at the end of the file (#p_fired2 at first, then modifies it to #p_fired1 and then erase it). I hope that keeping track of when it triggers the EMP this way is not too borderline.

Command line should be Rscript ReadyAimShoot.R, followed by the argument as in the example, at least on UNIX systems but probably as well on windows (I'll check that when I ll actually test it against the other bots).

Edit: Since the R version seems to have problem parsing the input, here is a python version of the same bot with, I hope, works. If any other R programmer see the post and see what's wrong with this bot, feel free to debug!

import sys, os

def Position(arena, element):
    y = [i for i,j in enumerate(arena) if element in arena[i]][0]
    x = arena[y].index(element)
    return (x,y)

def Direction(coord1, coord2):
    d0 = coord1[0]-coord2[0]
    d1 = coord1[1]-coord2[1]
    if d1!=0:
        a = ['N','S'][d1<0]
    else: a = ""
    if d0!=0:
        b = ['W','E'][d0<0]
    else: b = ""
    return a+b

def Shortest(coord1,coord2):
    d = abs(coord1[0]-coord2[0])-abs(coord1[1]-coord2[1])
    if d>0: a = 'EW'
    if d<=0: a = 'NS'
    return a

input = sys.argv[1].splitlines()
arena = input[0:10]
life = input[10].split(" ")
stuff = input[12:]
path = os.path.dirname(__file__)
f1 = os.path.join(path,'state','RAS')
try:
    with open(f1, 'r') as f:
        fired = int(f.read())
except:
    fired = 0

me = Position(arena, "Y")
other = Position(arena, "X")
target = Direction(me,other)
m = []
if len(stuff):
    s = [i.split(" ") for i in stuff]
    for i in s:
        if i[0]=='L': m += [(int(i[1]),int(i[2]))]


near = [(me[0]+i,me[1]) for i in range(-1,2,2)]+[(me[0],me[1]+i) for i in range(-1,2,2)]+[(5+me[0],5+me[1]) for i in range(-1,2,2)]
closeMines = [i for i in m if i in near]
dirmines = []
for j in closeMines:
    dirmines += Direction(me, j)


if target in ['N','S','E','W']:
    if int(life[1])>1 and fired==0:
        action = "P"
        with open(f1,'w') as f:
            f.write('2')
    else:
        if fired==2:
            action = "M "+target
            with open(f1,'w') as f:
                f.write('1')
        if fired==1:
            action = "B "+target
            with open(f1,'w') as f:
                f.write('0')
        if int(life[1])==1:
            action = "M "+target
else:
    s = Shortest(me,other)
    d1 = Direction((me[0],other[1]), other)
    d2 = Direction((other[0],me[1]), other)
    if s=='EW' and d1 not in dirmines:
        action = d1
    if s=='NS' and d2 not in dirmines:
        action = d2
    else:
        if d2 not in dirmines: action = d2
        if d1 not in dirmines: action = d1
        else: action = 0


sys.stdout.write(action)

Answer 4

EvadeBot

This bot prioritizes staying alive. If it detects incoming collisions, it tries to move to a safe spot by checking that spot for collisions. If there are no surrounding "safe" spots, it stays put and goes to the next step.

If there were no collisions (or safe spots in case of collision), it does an attack check. If the opponent is 8-axis aligned, it fires 80% of the time. If it's not aligned, it fires 50% of the time in the nearest heading. It chooses a weapon based on distance. If it's close, a landmine or bullet(depending on exact distance and relative health), missiles from afar.

If it decided not to fire, it takes a random walk(again checking for safe spots).

If none of the above worked out, it just sits there until the next turn.

It doesn't use EMP, and I have a bad feeling about squaring up against ReadyAimShoot, but we'll see how it goes.

---

The code is in two pieces. Since I may make more than one bot, I created an abstract BattleBot class. It includes helper functions like reading the arena, collision checking, heading management, etc. There's also a log function to help track what's going on while debugging. If debug==false, it will only print the actual output. If anyone wants to use/extend it, feel free. It's not pretty code, but it beats writing boilerplate.

BattleBot.java

import java.awt.Point;
import java.util.Random;

abstract class BattleBot {
    static boolean debug;

    Random rand;
    final String[] headings = {"N","NE","E","SE","S","SW","W","NW"};
    final int           BULLET      = 0,
                        MISSILE     = 1,
                        LANDMINE    = 2;

    final int arenaSize = 10;
    final Point center  = new Point(arenaSize/2, arenaSize/2);

    boolean valid = false;
    Weapon[] weapons;
    Point xPosition, yPosition; 
    int xEnergy, yEnergy;

    abstract String execute();

    Point nextPosition(int heading, Point from){
        if(from == null)
            from = yPosition;
        Point next = new Point(from);
        if(heading<0||heading>7)
            return next; 
        if(heading<2 || heading>6)
            next.y--;
        if(heading<6 && heading>2)
            next.y++;
        if(heading>4)
            next.x--;
        if(heading<4 && heading>0)
            next.x++;
        return next;        
    }

    boolean isHeadingExact(int heading, Point from, Point to){
        Point next = new Point(from);
        while(!isOutside(next)){
            next = nextPosition(heading, next);
            if(next.equals(to))
                return true;
        }
        return false;
    }

    int headingToPoint(Point to){
        int x = yPosition.x - to.x;
        int y = yPosition.y - to.y;
        if(x<0){
            if(y<0) return 3;
            if(y>0) return 1;
            return 2;
        }else if(x>0){
            if(y<0) return 5;
            if(y>0) return 7;
            return 6;
        }else{
            if(y<0) return 4;
            return 0;
        }
    }

    BattleBot(String[] args){
        rand = new Random();
        if(args.length < 1 || args[0].length() < arenaSize*arenaSize)
            return;
        String[] lines = args[0].split("\\r?\\n");
        if(lines.length<12)
            return;
        weapons = new Weapon[lines.length - 12];
        int wIndex = 0;
        for(int i=0;i<lines.length;i++){
            String line = lines[i];
            if(i<arenaSize){
                if(line.contains("X"))
                    xPosition = new Point(line.indexOf("X"),i);
                if(line.contains("Y"))
                    yPosition = new Point(line.indexOf("Y"),i);
            } else {
                String[] tokens = line.split(" ");
                switch(tokens[0].charAt(0)){
                case 'X':
                    xEnergy = Integer.parseInt(tokens[1]);
                    break;
                case 'Y':
                    yEnergy = Integer.parseInt(tokens[1]);
                    break;
                case 'B':
                case 'M':
                case 'L':
                    weapons[wIndex++] = new Weapon(tokens);
                    break;
                }
            }
        }
        valid = true;
    }

    int distance(Point a, Point b){
        return Math.max(Math.abs(a.x-b.x), Math.abs(a.y-b.y));
    }

    Point spotCollision(Point pos){
        for(int i=0;i<weapons.length;i++){
            Point collision = weapons[i].collisionPoint(pos);
            if(collision != null){
                log("Collision at " + collision.x + "," + collision.y + " with weapon type " + weapons[i].type);
                if(collision.equals(pos))
                    return collision;
                else if(weapons[i].type==MISSILE && distance(collision,pos) < 2)
                    return collision;
                log("Collision disregarded");
            }
        }
        return null;
    }

    boolean isOutside(Point pos){
        if(pos.x<0||pos.y<0||pos.x>=arenaSize||pos.y>=arenaSize)
            return true;
        return false;
    }

    static <T> void log(T msg){
        if(debug) System.out.println(msg);
    }

    int getHeading(String in){
        for(int i=0;i<headings.length;i++){
            if(in.equalsIgnoreCase(headings[i]))
                return i;
        }
        return -1;
    }

    class Weapon{

        final int[] speeds = {3,2,0};   
        Point position;
        int type;
        int heading;
        int speed;

        Weapon(String[] tokens){
            char which = tokens[0].charAt(0);
            type = which=='B'?BULLET:
                   which=='M'?MISSILE:
                              LANDMINE;

            speed = speeds[type];

            position = new Point(Integer.parseInt(tokens[1]), Integer.parseInt(tokens[2]));

            if(type==BULLET || type == MISSILE)
                heading = getHeading(tokens[3]);
            else
                heading = -1;
        }

        Point collisionPoint(Point pos){
            Point next = new Point(position);
            if(type==LANDMINE)
                return next;
            for(int i=0;i<speed;i++){
                next = nextPosition(heading, next);
                if(isOutside(next))
                    return next;
                if(next.equals(xPosition) || next.equals(yPosition))
                    return next;
                if(next.equals(pos))
                    return next;
            }
            return null;            
        }
    }   
}

This particular bot is EvadeBot. To compile/run, put it in a folder with BattleBot.java and run:

javac EvadeBot.java
java EvadeBot <arena-argument>

If you omit the argument or it can't parse it correctly, it defaults to "0" output.

EvadeBot.java

import java.awt.Point;

public class EvadeBot extends BattleBot{

    String output = "0";

    public static void main(String[] args){
        System.out.print(new EvadeBot(args).execute());
    }

    EvadeBot(String[] args) {
        super(args);
        debug = false;
    }

    @Override
    String execute() {
        if(!valid)
            return output;
        if(evade())
            return output;
        if(attack())
            return output;
        if(walk())
            return output;
        return output;
    }

    boolean evade(){
        Point collision = spotCollision(yPosition);
        if(collision!=null){
            log("Incoming! " + collision.x + "," + collision.y);
            return moveAwayFrom(collision);
        }
        return false;
    }

    boolean attack(){
        int dist = distance(yPosition, xPosition);
        int heading = headingToPoint(xPosition);
        int odds = rand.nextInt(100);

        if(isHeadingExact(heading, yPosition, xPosition)){
            if(odds<20)
                return false;
        } else {
            if(odds<50)
                return false;
        }
        log("Odds of firing " + headings[heading] + " to " + xPosition.x + "," + xPosition.y + " checked, preparing to attack.");
        if(dist==2){
            if(yEnergy > 3 || (xEnergy < 2 && yEnergy > 1)){
                output = "L " + headings[heading]; 
                return true;
            }
        }else if(dist<4){
            output = "B " + headings[heading];
            return true;
        }else{
            output = "M " + headings[heading];
            return true;
        }
        return false;
    }

    boolean walk(){
        log("Trying to random walk...");
        int heading = rand.nextInt(8);
        for(int i=0;i<8;i++,heading=(heading+1)%8){
            Point next = nextPosition(heading, yPosition);
            if(!isOutside(next) && spotCollision(next)==null){
                output = headings[heading];
                return true;
            }
        }
        return false;
    }

    boolean moveAwayFrom(Point from){
        int heading;
        if(from.equals(yPosition))
            heading = rand.nextInt(8);
        else
            heading = (headingToPoint(from) + (rand.nextBoolean()?2:6)) % 8;
        Point next = nextPosition(heading, yPosition);
        for(int i=0;i<8;i++){
            log("Checking move " + headings[heading] + " to " + next.x + "," + next.y);
            if(!isOutside(next) && spotCollision(next)==null){
                output = headings[heading];
                return true;
            }
            heading = (heading + 1) % 8;
            next = nextPosition(heading, yPosition);
        }
        return false;
    }
}

Answer 5

Spiral Bot Literate Haskell

In literate haskell, comments are default, so this entire post is the program. This bot will shoot missiles in spirals around it, ignoring input. It stores state in a file (which hopefully isn't being posioned by the competer.)

> import System.Directory (doesFileExist, createDirectoryIfMissing, setCurrentDirectory)
> import Control.Monad (unless)

First we list the missile actions.

> missiles = map ("M "++) $ cycle ["N", "NE", "E", "SE", "S", "SW", "W", "NW"]

Next we go straight into the IO monad. If "spiral.txt" doesn't exist, we write "0" to it. We also check for the directory.

> main = do
>   createDirectoryIfMissing True "state"
>   setCurrentDirectory "state"
>   exists <- doesFileExist "spiral.txt"
>   unless exists $ writeFile "spiral.txt" "0"

Then we read it and print the action.

>   actPos <- fmap read $ readFile "spiral.txt" :: IO Int
>   putStr $ missiles !! actPos

And finally we write to the file the now position.

>   writeFile "spiral.txt" (show $ actPos + 1)

Answer 6

King's Last Stand

An extension to my BattleBot, this is designed to combat EMP-blasters. The only sensible way (IMO) to use EMP is by firing it while you're on the same axis as the opponent, then shooting missiles/weapons toward the stuck opponent. So, I stay off the axis :)

If you've ever had a chess game go down to a king against a king+queen, you know that a queen alone can't checkmate, you have to get the king involved. If you don't, the lone king's strategy is easy: try to stay off-axis and toward the center to maximize mobility. If you get stuck, go for a stalemate.

Of course, there is no great way to force a stalemate here, so eventually you get stuck on a side or corner if the queen is playing at any level of competence. If this bot is ever in that situation, it shoots. Assuming the opponent is going to EMP, this gives a one-turn damage advantage, so the king's last stand should turn out alright unless he's already low on life.

Oh, and if it's already off-axis and safe from projectiles, it'll just take a potshot in the general direction of the enemy.

LastStand.java

import java.awt.Point;
import java.util.ArrayList;

public class LastStand extends BattleBot{

    String output = "0";
    ArrayList<Point> safeFromEnemy;
    ArrayList<Point> safeFromWeapons;
    ArrayList<Point> safeFromBoth;

    public static void main(String[] args){
        System.out.print(new LastStand(args).execute());
    }

    LastStand(String[] args){
        super(args);
        debug = false;
    }

    @Override
    String execute() {
        findSafeSpots();
        if(attack())
            return output;
        if(evade(safeFromBoth))
            return output;
        if(evade(safeFromEnemy))
            return output;

        return output;
    }

    boolean evade(ArrayList<Point> points){
        Point dest = closestToCenter(points);
        if(dest==null)
            return false;
        int heading = headingToPoint(dest);
        output = headings[heading];
        return true;
    }

    boolean attack(){
        if(safeFromEnemy.isEmpty() || safeFromBoth.contains(yPosition))
            return fire();
        return false;
    }

    Point closestToCenter(ArrayList<Point> points){
        Point closest = null;
        int dist = 15;
        for(Point pos : points){
            if(distance(center, pos) < dist){
                closest = pos;
                dist = distance(center, pos);
            }
        }
        return closest;
    }

    boolean isOnEnemyAxis(Point pos){
        int x = Math.abs(pos.x - xPosition.x);
        int y = Math.abs(pos.y - xPosition.y);
        if(x==0 || y==0 || x==y)
            return true;
        return false;
    }

    void findSafeSpots(){
        safeFromEnemy = new ArrayList<Point>();
        safeFromWeapons = new ArrayList<Point>();
        safeFromBoth = new ArrayList<Point>();

        if(!isOnEnemyAxis(yPosition))
            safeFromEnemy.add(yPosition);
        if(spotCollision(yPosition)==null)
            safeFromWeapons.add(yPosition);

        for(int heading=0;heading<8;heading++){
            Point pos = nextPosition(heading, yPosition);
            if(isOutside(pos))
                continue;
            if(!isOnEnemyAxis(pos))
                safeFromEnemy.add(pos);
            if(spotCollision(pos)==null)
                safeFromWeapons.add(pos);
        }
        for(Point pos : safeFromEnemy){
            if(safeFromWeapons.contains(pos))
                safeFromBoth.add(pos);
        }
    }

    boolean fire(){
        int heading = headingToPoint(xPosition);
        int dist = distance(xPosition, yPosition);
        if(dist>1 || yEnergy>4)
            output = "M " + headings[heading];
        else
            output = "B " + headings[heading];
        return true;
    }   
}

To compile run, place in a folder with BattleBot.java and run:

javac LastStand.java
java LastStand <arena-argument>

Answer 7

DodgingTurret

a Python Bot

Here's another attempt. Since ReadyAimShoot is in the repair shop for a while :) I figured I'll try something else in the meantime, using Python this time.

import sys

def Position(arena, element):
    y = [i for i,j in enumerate(arena) if element in arena[i]][0]
    x = arena[y].index(element)
    return (x,y)

def Direction(coord1, coord2):
    d0 = coord1[0]-coord2[0]
    d1 = coord1[1]-coord2[1]
    if d1!=0:
        a = ['N','S'][d1<0]
    else: a = ""
    if d0!=0:
        b = ['W','E'][d0<0]
    else: b = ""
    return a+b

def GetPath(coord, direction):
    if direction=='N': path = [(coord[0],coord[1]-i) for i in xrange(3)]
    if direction=='S': path = [(coord[0],coord[1]+i) for i in xrange(3)]
    if direction=='E': path = [(coord[0]+i,coord[1]) for i in xrange(3)]
    if direction=='W': path = [(coord[0]-i,coord[1]) for i in xrange(3)]
    if direction=='NE': path = [(coord[0]+i,coord[1]-i) for i in xrange(3)]
    if direction=='NW': path = [(coord[0]-i,coord[1]-i) for i in xrange(3)]
    if direction=='SE': path = [(coord[0]+i,coord[1]+i) for i in xrange(3)]
    if direction=='SW': path = [(coord[0]-i,coord[1]+i) for i in xrange(3)]
    return path

def Danger(coord, stuff):
    if len(stuff):
        s = [i.split(" ") for i in stuff]
        for i in s:
            if i[0] in ['M','B']:
                path = GetPath((int(i[1]),int(i[2])),i[3])
                if coord in path:
                    return ['unsafe',path]
        return ['safe',()]
    else:
        return ['safe',()]

input = sys.argv[1].splitlines()
arena = input[0:10]
stuff = input[12:]
me = Position(arena, "Y")
center = Direction(me, (5,5))
if center != "":
    action = center
else:
    d = Danger(me,stuff)
    if d[0]=='safe':
        other = Position(arena,"X")
        target = Direction(me, other)
        action = 'M '+target
    if d[0]=='unsafe':
        escape = [(me[0]+i,me[1]) for i in range(-1,2,2)]+[(me[0],me[1]+i) for i in range(-1,2,2)]+[(5+me[0],5+me[1]) for i in range(-1,2,2)]
        esc_choice = [i for i in escape if i not in d[1]][0]
        action = Direction(me,esc_choice)

sys.stdout.write(action)

I shamelessly stole the line sys.argv[1].splitlines() from @Gareth but at least this time that means I won't have a problem parsing the input.

This bot runs at the center at the start of the bout, then stays there and shoots missiles in the direction of the opponent. He also tries to dodge nearby bullets and missiles if it's on their path but then goes back to the center before starting shooting again.

Answer 8

Straight shooter

This is another simple bot you can use for testing. If it has a direct line of sight to the opponent it shoots, otherwise it steps randomly.

import sys
try:
  map = sys.argv[1][0:110].split()
except:
  sys.exit(1)

# Locate us and the opponent.
#
for y in range(0,10):
  for x in range(0, 10):
    if 'Y' == map[y][x]:
      me_y = y
      me_x = x
    elif 'X' == map[y][x]:
      him_y = y
      him_x = x

# If we're on a direct line with the opponent, fire a missile.
#
if me_y == him_y or me_x == him_x or abs(me_y - him_y) == abs(me_x - him_x):
  if   him_y < me_y and him_x < me_x:
    sys.stdout.write('M NW')
  elif him_y < me_y and him_x == me_x:
    sys.stdout.write('M N')
  elif him_y < me_y and him_x > me_x:
    sys.stdout.write('M NE')
  elif him_y == me_y and him_x < me_x:
    sys.stdout.write('M W')
  elif him_y == me_y and him_x > me_x:
    sys.stdout.write('M E')
  elif him_y > me_y and him_x < me_x:
    sys.stdout.write('M SW')
  elif him_y > me_y and him_x == me_x:
    sys.stdout.write('M S')
  elif him_y > me_y and him_x > me_x:
    sys.stdout.write('M SE')

# Otherwise, move randomly.
#
else:
  import random
  sys.stdout.write(random.choice(['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW']))

Answer 9

CamperBot

This bot just stays where he is and shoots. I only implemented bullets, as the other weapons would harm the bot. Please forgive me my awful C-skills ;)

#include <stdio.h>
#include <time.h>

int main(int argc, char *argv[])
{
    int direction = 0;
    char directions[][3] = {"N", "NE", "E", "SE", "S", "SW", "W", "NW"};
    srand(time(NULL));

    direction = rand() % 8;
    printf("B %s", directions[direction]);
    return 0;
}

Not really expected to win much.

Answer 10

neo-bot

coffeescript

Another JavaScript bot to add to the mix. This one targets Node.js and is written in CoffeeScript. The architecture follows from the Java crowd with a base class handling general bottiness and another file with specialization for the bot at hand.

The main strategy of this bot is to not get hit by your projectiles. If you aren't an immediate threat neo-bot will just start shooting.

The base file shared.coffee

# entry point

deserializeBoard = (board) ->
  me = no
  you = no
  rows = board.split '\n'
  all = for i in [0...rows.length]
    row = rows[i]
    me = row: i, col: row.indexOf 'Y' if /Y/.test row
    you = row: i, col: row.indexOf 'X' if /X/.test row
    row.split ''
  throw new Error "missing player" unless me and you
  all.me = me
  all.you = you
  all

deserializeState = (state) ->
  board = deserializeBoard state[0...110]
  rest = state[110...]
    .split '\n'
    .filter (d) -> d
  if rest[0][0] is 'Y'
    board.me.health = +rest[0][2...]
    board.you.health = +rest[1][2...]
  else
    board.you.health = +rest[0][2...]
    board.me.health = +rest[1][2...]
  board.mines = []
  board.projectiles = []
  for weapon in rest[2...]
    parts = weapon[2...].split ' '
    if weapon[0] is 'L'
      board.mines.push
        row: +parts[1]
        col: +parts[0]
    else
      board.projectiles.push
        type: weapon[0]
        row: +parts[1]
        col: +parts[0]
        dir: parts[2]
  board

module.exports = bot = (handle) ->

  state = process.argv[-1...][0]
  board = deserializeState state

  move = handle board
  process.stdout.write move

And neo-bot.coffee, the bot code.

# i know kung fu

bot = require "./shared"

board_rows = [0...10]
board_cols = [0...10]

directions = [
  'NW', 'N', 'NE'
   'W',       'E'
  'SW', 'S', 'SE'
]

direction = (a, b) ->
  if a.row < b.row
    if a.col < b.col
      "SE"
    else if a.col is b.col
      "S"
    else
      "SW"
  else if a.row is b.row
    if a.col < b.col
      "E"
    else
      "W"
  else
    if a.col < b.col
      "NE"
    else if a.col is b.col
      "N"
    else
      "NW"

move = (me, dir) ->
  row = me.row
  col = me.col
  if /N/.test dir
    row--
  if /S/.test dir
    row++
  if /W/.test dir
    col--
  if /E/.test dir
    col++
  {row, col}

clamp = (v) ->
  Math.max 0, Math.min 9, v

legal = (pos) ->
  clamp(pos.row) is pos.row and clamp(pos.col) is pos.col

randOf = (choices) ->
  i = Math.floor Math.rand * choices.length
  choices[i]

moves =
  B: 3
  M: 2

damage =
  B: 1
  M: 3

danger = (board) ->
  n = ((0 for i in [0...10]) for j in [0...10])
  for projectile in board.projectiles
    next = projectile
    for i in [0...moves[projectile.type]]
      next = move next, projectile.dir
      if projectile.type is 'M' and not legal next
        for d in directions
          schrapnel = move next, d
          if legal schrapnel
            n[schrapnel.row][schrapnel.col] += 1
      continue unless legal next
      n[next.row][next.col] += damage[projectile.type]
  for mine in board.mines
    n[mine.row][mine.col] += 2
  n

warning = (board) ->
  n = ((0 for i in [0...10]) for j in [0...10])
  for dir in directions
    p = board.you
    p = move p, dir
    continue unless legal p
    n[p.row][p.col] = damage.M - 1 # relative damage
    p = move p, dir
    continue unless legal p
    n[p.row][p.col] = damage.M
    p = move p, dir
    continue unless legal p
    n[p.row][p.col] = damage.B
  for mine in board.mines
    for dir in directions
      p = move mine, dir
      continue unless legal p
      n[p.row][p.col] += 1
  n

board_map = (map) ->
  (a) ->
    ((map a[i][j] for j in board_cols) for i in board_rows)

board_pair = (join) ->
  (a, b) ->
    ((join a[i][j], b[i][j] for j in board_cols) for i in board_rows)

boards =
  sum: board_pair (a, b) -> a + b
  scale: (n) -> board_map (a) -> a * n

chooseSafeDir = ({me, you}, lava) ->
  dirs = []
  min = +Infinity
  for dir in directions
    guess = move me, dir
    continue unless legal guess
    guess.dir = dir
    guess.damage = lava[guess.row][guess.col]
    min = guess.damage if guess.damage < min
    dirs.push guess
  dirs.sort (a, b) ->
    if a.damage < b.damage
      -1
    else if b.damage < a.damage
      1
    else
      0
  choice = randOf dirs.filter (d) ->
    d.damage < min + 1
  choice = choice or dirs[0]
  choice.dir

neo = (WARNING_FACTOR, MISSILE_FACTOR, MOVE_FACTOR) ->
  WARNING_FACTOR ?= 0.8
  MISSILE_FACTOR ?= 0.2
  MOVE_FACTOR ?= 0.1

  combine = (d, w) ->
    boards.sum d, boards.scale(WARNING_FACTOR)(w)

  shoot = ({me, you}) ->
    weapon = if Math.random() < MISSILE_FACTOR then 'M' else 'B'
    dir = direction me, you
    "#{weapon} #{dir}"

  (board) ->
    lava = combine danger(board), warning(board)

    if lava[board.me.row][board.me.col] or Math.random() < MOVE_FACTOR
      chooseSafeDir board, lava
    else
      shoot board

bot neo()

I'd highly recommend compiling the coffee files to javascript before running; it's quite a bit faster. Basically you want to do this:

> coffee -c *.coffee
> ./bb "java EvilBot" "node ./neo-bot.js"

Answer 11

Since there are no entries yet I'll put one out there so you have something to beat up. I give to you:

Mine! Mine! Mine!

import sys
import random
from itertools import product

def getMyPos(arena):
    x=0
    y=0
    for idx, line in enumerate(arena):
        if(line.find('Y')!= -1):
            x=line.find('Y')
            y=idx
    return [x, y]

def isNearMine(pos, badstuff):
    returnval=False
    for badthing in badstuff:
        thinglist=badthing.split(" ")
        if(thinglist[0]=='L'):
            returnval=returnval or isNear(pos, map(int, thinglist[1:3]))
    return returnval

def isNear(pos1, pos2):
    return ((abs(pos1[0]-pos2[0])<2) and (abs(pos1[1]-pos2[1])<2))

def newpos(mypos, move):
    return [mypos[0]+move[0], mypos[1]+move[1]]

def inBounds(pos):
    return pos[0]<10 and pos[0]>=0 and pos[1]<10 and pos[1]>=0

def randomSafeMove(arena, badstuff):
    mypos=getMyPos(arena)
    badsquares=[mypos] #don't want to stay still
    for badthing in badstuff:
        thinglist=badthing.split(" ")
        if(thinglist[0]=='L'):
            badsquares.append(map(int, thinglist[1:3]))
    possiblemoves=list(product(range(-1, 2), repeat=2))
    possiblemoves=[list(x) for x in possiblemoves]
    safemoves=[x for x in possiblemoves if newpos(mypos, x) not in badsquares]
    safemoves=[x for x in safemoves if inBounds(newpos(mypos, x))]
    move=random.choice(safemoves)
    return (("N S"[move[1]+1])+("W E"[move[0]+1])).strip()

def randomDropMine(arena):
    mypos=getMyPos(arena)
    badsquares=[mypos] #don't want to drop a mine under myself
    possiblemoves=list(product(range(-1, 2), repeat=2))
    possiblemoves=[list(x) for x in possiblemoves]
    possiblemoves=[x for x in possiblemoves if newpos(mypos, x) not in badsquares]
    possiblemoves=[x for x in possiblemoves if inBounds(newpos(mypos, x))]
    move=random.choice(possiblemoves)
    return "L "+(("N S"[move[1]+1])+("W E"[move[0]+1])).strip()

input=sys.argv[1].splitlines()
arena=input[0:10]
energy=input[10:12]
badstuff=input[12:]

if(isNearMine(getMyPos(arena), badstuff)):
    sys.stdout.write(randomSafeMove(arena, badstuff))
else:
    sys.stdout.write(randomDropMine(arena))

Doesn't do anything particularly clever. Drops a mine if there are none in any of the surrounding squares otherwise moves into one of the safe surrounding squares. Can only barely beat the HuggyBot.

Please excuse the naff Python coding.

Answer 12

Random bot

This bot just makes a random action on each move. It doesn't fire the EMP and it doesn't look at the map at all. Half the time it's just firing into the wall!

#include <stdio.h>
#include <sys/time.h>

void main(int argc, char **argv)
{
  char dirs[][3] = {"N", "NE", "E", "SE", "S", "SW", "W", "NW"};

  struct timeval tv;
  gettimeofday(&tv, NULL);
  srand(tv.tv_usec);

  int action = rand()%11;
  int dir = rand()%7;

  switch(action)
  {
    case 8:
      printf("B %s", dirs[dir]);
      break;

    case 9:
      printf("M %s", dirs[dir]);
      break;

    case 10:
      printf("L %s", dirs[dir]);
      break;

    default:
      printf(dirs[action]);
      break;
  }
}

Test it (against itself) as below.

$ gcc random.c -o random
$ ./bb random

Answer 13

Trouble and Strafe

Some Ruby representation in the fight. Moves up and down the randomly assigned wall firing missiles at the opposite wall. Slightly glitchy at the top and bottom.

def getInput()
    inputlines=ARGV[0].split(/\n/)
    return [inputlines[0, 10], inputlines[10, 2], inputlines[12..-1]]
end

def getMyPos(arena)
    pos=[]
    arena.each_with_index{|str, index| pos=[str.index('Y'), index] if(!str.index('Y').nil?)}
    return pos
end

def parseProjectiles(projectiles)
    projectiles.map!{|prj| prj.split(' ')}
    missiles=projectiles.select{|prj| prj[0]=='M'}
    bullets=projectiles.select{|prj| prj[0]=='B'}
    landmines=projectiles.select{|prj| prj[0]=='L'}
    return [missiles, bullets, landmines]
end

def haveFired?(ypos, direction, projectiles)
    return projectiles.select{|prj| prj[2]==ypos.to_s && prj[3]==direction}.size>0
end

arena, botenergy, projectiles=getInput()
missiles, bullets, landmines=parseProjectiles(projectiles)

myposX=getMyPos(arena)[0]
myposY=getMyPos(arena)[1]

direction="WE"[myposX!=0 ? 0 : 1]

if haveFired?(myposY, direction, missiles)
    if myposY==0
        print "S"
    elsif myposY==9
        print "N"
    else
        if haveFired?(myposY-1, direction, missiles)
            print "S"
        elsif haveFired?(myposY+1, direction, missiles)
            print "N"
        else
            if(Random.rand(2)==0)
                print "N"
            else
                print "S"
            end
        end
    end
else
    print "M "+direction
end

Answer 14

A JavaScript core

I thought I'd be kind and give you my core JS bot. It's got all the functions necessary for making a bot, all you need is some actions to do based on the data that this gives you. Not finished yet, as I can't really test it (can't get the arena code to compile).

Feel free to use this, I'm looking forward to seeing some JS bots in the mix.

To Do:

• Add functions to calculate weapon locations

  var stdi = WScript.StdIn;
  var stdo = WScript.StdOut;
  
  function botLog(toLog){
      var fso  = new ActiveXObject("Scripting.FileSystemObject");
      var fh = fso.CreateTextFile("./botLog.txt", 8, true);
      fh.WriteLine(toLog); 
      fh.Close(); 
  }
  
  var directions = ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW'];
  
  // READ ARGUMENTS AND CREATE THE ARENA
  var arena = {};
  
  arena.map = WScript.Arguments.Item(0); // Get the arena from arguments
  arena.rows = arena.map.split('\\n');
  
  
  arena.find = function(toFind){ //Find a character in the arena.
      for(var i = 0; i < 10; i++){
          if(arena.rows[i].indexOf(toFind) !== -1){
              return [arena.rows[i].search(toFind), i];
          }
      }
  };
  arena.findAtPos = function(x, y){
      return arena.rows[y].charAt(x);
  };
  
  me = {};
      me.pos = arena.find('Y');
      me.x = me.pos[0];
      me.y = me.pos[1];
      me.energy = parseInt(arena.rows[10].replace("Y ", ""));
      me.nearby = {
          N : arena.findAtPos(me.x, me.y - 1),
          NE : arena.findAtPos(me.x + 1, me.y - 1),
          E : arena.findAtPos(me.x + 1, me.y),
          SE : arena.findAtPos(me.x + 1, me.y + 1),
          S : arena.findAtPos(me.x, me.y + 1),
          SW : arena.findAtPos(me.x - 1, me.y + 1),
          W : arena.findAtPos(me.x - 1, me.y),
          NW : arena.findAtPos(me.x -1, me.y - 1),
  
          contains : function(checkFor){
              for(var j = 0; j < 8; j++){
                  if(me.nearby[j] === checkFor){
                      return true;
                  }
              }
          }
      }
  
  foe = {};
      foe.pos = arena.find('X');
      foe.x = foe.pos[0];
      foe.y = foe.pos[1];
      foe.energy = parseInt(arena.rows[11].replace("X ", ""));
  

Please note that some things here may have to be modified for other OS (this works only on Windows). Rhino version here: http://pastebin.com/FHvmHCB8

Answer 15

Centre-Bot

A JavaScript Bot

This bot aims to get into the middle of the arena, before it shoots bullets or missiles at it's target each turn depending on how close it is. If the enemy is in the middle, it'll just keep shooting bullets in the vague direction.

I don't expect it to do very well, but it's more of a testing one, and I'm interested to see how well it really does.

    var arena = {};
var sys = require("sys");
var fs = require("fs");

arena.map = process.argv[2];
arena.rows = arena.map.split('\n');


arena.find = function(toFind){
    for(var i = 0; i < 10; i++){
            if(arena.rows[i].indexOf(toFind) !== -1){
                return [arena.rows[i].search(toFind), i];
            }
    }
};
arena.findAtPos = function(x, y){
    return arena.rows[y].charAt(x);
};

me = {};
    me.pos = arena.find('Y');
    me.x = me.pos[0];
    me.y = me.pos[1];
    me.energy = parseInt(arena.rows[10].replace("Y ", ""));

foe = {};
    foe.pos = arena.find('X');
    foe.x = foe.pos[0];
    foe.y = foe.pos[1];
    foe.energy = parseInt(arena.rows[11].replace("X ", ""));
function findFoe(){ 
    if(me.x < foe.x){
        if(me.y < foe.y){
            foe.direction = 'SE';
        }
        else if(me. y  === foe.y){
            foe.direction  = 'E';
        }
        else{
            foe.direction = 'NE';
        }
    }
    if(me.x === foe.x){
        if(me.y < foe.y){
            foe.direction = 'S';
        }
        else{
            foe.direction = 'N';
        }
    }
    if(me.x > foe.x){
        if(me.y < foe.y){
            foe.direction = 'SW';
        }
        else if(me. y  === foe.y){
            foe.direction  = 'W';
        }
        else{
            foe.direction = 'NW'
        }
    }
}

function findCentre(){
    if(me.x < 5){
        if(me.y < 5){
            centreDirection = 'SE';
        }
        else if(me.y  === 5){
            centreDirection  = 'E';
        }
        else{
            centreDirection = 'NE'
        }
    }
    if(me.x === 5){
        if(me.y < 5){
            centreDirection = 'S';
        }
        else{
            centreDirection = 'N'
        }
    }
    if(me.x > 5){
        if(me.y < 5){
            centreDirection = 'SW';
        }
        else if(me. y  === 5){
            centreDirection  = 'W';
        }
        else{
            centreDirection = 'NW'
        }
    }
}
findCentre();
findFoe();
if(me.x !== 5 && me.y !== 5){
    process.stdout.write(centreDirection);
}else{
    if(foe.x >= me.x + 2 || foe.x <= me.x - 2  || foe.y >= me.y + 2 || foe.y <= me.y - 2){
        process.stdout.write('M ' + foe.direction);
    }else process.stdout.write('B ' + foe.direction);
}

save as .js file and execute with node centrebot.js. This will work with Node.js, but you may have to modify it for another program, sorry!

In my tests:

• Thrashed ReadyAimShoot without a scratch.
• MOSTLY wins against DodgingTurret
• Won all with a few scratches from lucky landmines from Randombot
• Beat Straight shooter 9 times out of 9, but each bout was close, even though I won all of them.

Haven't tested any of the top java bots, and I'm not too confident either...

Answer 16

CunningPlanBot (Python 3.3)

This is completely untested under the actual interface... It does work correctly with the maps at least!

It's written for Python 3.3

What it does:

If in Phase 1 - If at wall and direction moves into wall or moving into a landmine, randomly change direction to a non wall or landmine direction - Move in current direction - Go to Phase 2

If in Phase 2 - Shoot bullet in closest direction to enemy - Go to Phase 3

If in Phase 3 - If no land mine, drop land mine - Go to phase 1

Still needs to figure out whether to shoot a missile. Also I've got no clue whatsoever about whether the landmine avoiding stuff works. Needs more testing tomorrow evening.

#!/usr/bin/python
import sys
import os.path
import random
import math

def iround(x):
    return int(round(x) - .5) + (x > 0)   

currentphase = 0
currentdir = 0

#
#     4  
#   5   3  
# 6  DIR  2
#   7   1
#     0

if os.path.isfile('state/cpb'):
  statein = open('state/cpb', 'r')  
  currentdir = int(statein.read(1))
  currentphase = int(statein.read(1))
  statein.close()

Landmines = []    

#Loads the map bit. The bits we care about anyway.
line=sys.argv[1].splitlines()
for y in range(0, 10):
  for x in range(0, 10):
    if line[x][y] == "X":
      hisloc = (x, y)
    elif line[x][y] == "Y":    
      myloc = (x, y)
    elif line[x][y] == "L":
      Landmines.append((x,y))

#print(myloc[0])
#print(myloc[1])

newdir = False
if (currentphase == 0):
  if (currentdir == 7) or (currentdir == 0) or (currentdir == 1) and (myloc[1] == 9):
    newdir = True
  if (currentdir == 5) or (currentdir == 4) or (currentdir == 3) and (myloc[1] == 0):
    newdir = True
  if (currentdir == 3) or (currentdir == 2) or (currentdir == 1) and (myloc[0] == 9):
    newdir = True
  if (currentdir == 5) or (currentdir == 6) or (currentdir == 7) and (myloc[0] == 0):
    newdir = True    
  if newdir:
    newdirs = []
    #Test 0
    if (myloc[1] < 9) and not (myloc[0], myloc[1] + 1) in Landmines:
      newdirs.append(0)
    #Test 1
    if (myloc[0] < 9) and (myloc[1] < 9) and not (myloc[0] + 1, myloc[1] + 1) in Landmines:
      newdirs.append(1)
    #Test 2
    if (myloc[0] < 9) and not (myloc[0] + 1, myloc[1]) in Landmines:
      newdirs.append(2)
    #Test 3
    if (myloc[0] < 9) and (myloc[1] > 0) and not (myloc[0] + 1, myloc[1] - 1) in Landmines:
      newdirs.append(3)      
    #Test 4
    if (myloc[1] > 0) and not (myloc[0], myloc[1] - 1) in Landmines:
      newdirs.append(4)
    #Test 5
    if (myloc[0] > 0) and (myloc[1] > 0) and not (myloc[0] - 1, myloc[1] - 1) in Landmines:
      newdirs.append(5)    
    #Test 6
    if (myloc[0] > 0) and not (myloc[0] - 1, myloc[1] ) in Landmines:
      newdirs.append(6)      
    #Test 7
    if (myloc[0] > 0) and (myloc[1] > 9) and not (myloc[0] - 1, myloc[1] + 1) in Landmines:
      newdirs.append(7)     
    if len(newdirs) == 0:
      if currendir == 0: currentdir = 4
      elif currendir == 1: currentdir = 5
      elif currendir == 2: currentdir = 6
      elif currendir == 3: currentdir = 7
      elif currendir == 4: currentdir = 0
      elif currendir == 5: currentdir = 1
      elif currendir == 6: currentdir = 2
      elif currendir == 7: currentdir = 3
    else:
      currentdir = random.SystemRandom().choice(newdirs)
  if currentdir == 0: print ("S", end="")
  elif currentdir == 1: print ("SE", end="")
  elif currentdir == 2: print ("E", end="")
  elif currentdir == 3: print ("NE", end="")
  elif currentdir == 4: print ("N", end="")
  elif currentdir == 5: print ("NW", end="")
  elif currentdir == 6: print ("W", end="")
  elif currentdir == 7: print ("SW", end="")

elif (currentphase == 1):
  dx = (myloc[0] - hisloc[0])
  dy = (myloc[1] - hisloc[1])
  distance = math.pow(dx*dx+dy*dy, 0.5)
  angle = int(iround(math.degrees(math.atan2(dx, -dy)) / 45) ) % 8
  if angle == 5: print ("B S", end="")
  elif angle == 1: print ("B SE", end="")
  elif angle == 2: print ("B E", end="")
  elif angle == 3: print ("B NE", end="")
  elif angle == 4: print ("B N", end="")
  elif angle == 5: print ("B NW", end="")
  elif angle == 6: print ("B W", end="")
  elif angle == 7: print ("B SW", end="") 

elif (currentphase == 2):
  if not (myloc in Landmines): print ("L", end="")

currentphase = (currentphase + 1) % 3    

stateout = open ('state/cpb', 'w')
stateout.write(str(currentdir))
stateout.write(str(currentphase))
stateout.close()

Answer 17

UltraBot

A Java bot that calculates the danger for each surrounding field. If a surrounding field is less dangerous than the current one, the bot moves there (or another, equally dangerous field). If there is no less dangerous field, the bot shoots (missiles if enemy bot is far away, bullets if enemy bot is close). I took some code from the BattleBot (thanks!).

import java.awt.Point;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;

public class UltraBot {
    private static final int arenaSize = 10;
    private static ArrayList<Weapon> weapons = new ArrayList<Weapon>();
    private static Bot me;
    private static Bot enemy;

    public static void main(String args[]) {
        Direction suggestedMove;
        readInput(args[0]);
        suggestedMove = suggestedMove();

        if (suggestedMove != Direction.STAY) {
            System.out.print(suggestedMove.name());
            return;
        }

        System.out.print(shootCmd());
    }

    public static void readInput(String args) {
        String[] lines = args.split("\\r?\\n");

        for(int i=0;i<lines.length;i++){
            String line = lines[i];
            if(i<arenaSize){
                if(line.contains("X"))
                    enemy = new Bot(new Field(line.indexOf("X"),i));
                if(line.contains("Y"))
                    me = new Bot(new Field(line.indexOf("Y"),i));
            } else {
                String[] tokens = line.split(" ");
                switch(tokens[0].charAt(0)){
                case 'X':
                    enemy.setLife(Integer.parseInt(tokens[1]));
                    break;
                case 'Y':
                    me.setLife(Integer.parseInt(tokens[1]));
                    break;
                default:
                    weapons.add(new Weapon(tokens));
                    break;
                }
            }
        }
    }

    public static Direction suggestedMove() {
        Map<Direction, Integer> surrFields = new HashMap<Direction, Integer>();
        Random rand = new Random();

        //calculate danger for all surrounding fields
        for(Direction direction : Direction.values()) {
            Field currField = me.getPos().incPos(direction, 1);
            surrFields.put(direction, currField.calcDanger(weapons, enemy));
        }

        int currDanger = surrFields.get(Direction.STAY);
        Direction currDirection = Direction.STAY;

        for (Entry<Direction, Integer> e : surrFields.entrySet()) {
            //always move if better field found
            if (e.getValue() < currDanger) {
                currDanger = e.getValue();
                currDirection = e.getKey();
            }
            //move sometimes if equal danger field found
            else if(e.getValue() == currDanger && rand.nextInt(3) == 1) {
                if (currDanger != 0 || rand.nextInt(15) == 1) {
                    currDanger = e.getValue();
                    currDirection = e.getKey();
                }
            }
        }
        return currDirection;
    }

    public static String shootCmd() {
        WeaponType type = WeaponType.M;

        if(me.getPos().isNear(enemy.getPos(), 3)) {
            type = WeaponType.B;
        }

        return type.name() + " " + me.shootDirection(enemy);
    }
}

class Bot {
    private Field pos;
    private int life;

    public Bot(Field pos) {
        this.pos = pos;
    }

    public void setLife(int life) {
        this.life = life;
    }

    public Field getPos() {
        return pos;
    }

    public int getLife() {
        return life;
    }

    public String shootDirection(Bot other) {
        Random rand = new Random();
        Direction direction = Direction.S;
        if (getPos().getX() >= other.getPos().getX() && getPos().getY() >= other.getPos().getY()) {
            switch(rand.nextInt(5)) {
                case 0: direction =  Direction.N; break;
                case 1: direction = Direction.W; break;
                default: direction = Direction.NW; break;
            }
        }
        else if (getPos().getX() <= other.getPos().getX() && getPos().getY() >= other.getPos().getY()) {
            switch(rand.nextInt(3)) {
                case 0: direction = Direction.N; break;
                case 1: direction = Direction.E; break;
                default: direction = Direction.NE; break;
            }
        }
        if (getPos().getX() >= other.getPos().getX() && getPos().getY() <= other.getPos().getY()) {
            switch(rand.nextInt(3)) {
                case 0: direction = Direction.S; break;
                case 1: direction = Direction.W;break;
                default: direction = Direction.SW;break;
            }
        }
        if (getPos().getX() <= other.getPos().getX() && getPos().y <= other.getPos().y) {
            switch(rand.nextInt(3)) {
                case 0: direction = Direction.S; break;
                case 1: direction = Direction.E; break;
                default: direction = Direction.SE; break;
            }
        }
        return direction.name();
    }
}

enum Direction {
    N(0, -1), NE(1, -1), E(1, 0), SE(1, 1), S(0, 1), SW(-1, 1), W(-1, 0), NW(-1,-1), STAY(0,0);

    public final int offsetX;
    public final int offsetY;

    Direction(int offsetX, int offsetY) {
        this.offsetX = offsetX;
        this.offsetY = offsetY;
    }
}

enum WeaponType {
    B(1, 3), M(3, 2), L(2, 0);

    public final int dmg;
    public final int speed;

    WeaponType(int dmg, int speed) {
        this.dmg = dmg;
        this.speed = speed;
    }
}

class Weapon {
    private WeaponType type;
    private Direction direction;
    private Field pos;

    public Weapon(String[] tokens) {
        this.type = WeaponType.valueOf(tokens[0]);
        this.pos = new Field(Integer.parseInt(tokens[1]), Integer.parseInt(tokens[2]));
        if(type != WeaponType.L) {
            this.direction = Direction.valueOf(tokens[3]);
        }
    }

    public int getDanger(Field dest) {

        if (dest.isOutside()) {
            return 99;
        }

        if (type == WeaponType.L) {
            return dest.equals(pos) ? type.dmg * 3 : 0; // stepped on landmine
        }

        for (int i = 1; i <= type.speed; i++) {
            Field newPos = pos.incPos(direction, i);

            if (dest.equals(newPos)) {
                return type.dmg * 3; // direct hit with missile or bullet
            }
        }

        return 0;
    }
}

class Field extends Point{

    public Field(int x, int y) {
        super(x,y);
    }

    // as it tries to stay off walls and enemy, it doesn't need to calc splash dmg

    public int calcDanger(ArrayList<Weapon> weapons, Bot enemy) {
        int danger = 0;

        // is near wall
        if (this.getX() == 0 || this.getX() == 9)
            danger++;
        if (this.getY() == 0 || this.getY() == 9)
            danger++;

        for (Weapon weapon : weapons) {
            danger += weapon.getDanger(this);
        }

        // near bot
        if (this.isNear(enemy.getPos(), 2)) {
            danger++;
        }

        return danger;
    }

    public Boolean isOutside() {
        if (this.getX() > 9 || this.getY() > 9 || this.getX() < 0 || this.getY() < 0) {
            return true;
        }
        return false;
    }

    public Boolean isNear(Field dest, int distance) {
        int dx = (int)Math.abs(dest.getX() - this.getX());
        int dy = (int)Math.abs(dest.getY() - this.getY());

        if (dx <= distance || dy <= distance) {
            return true;
        }
        return false;
    }

    public Field incPos(Direction direction, int step) {
        return new Field((int)this.getX() + (direction.offsetX * step), 
                (int)this.getY() + (direction.offsetY * step));
    }
}

This bot is extremely hard to hit, but not very good at shooting the enemy… I still expect it to be better than my previous CamperBot.

Answer 18

NinjaPy

A last minute submission in python (untested but hopefully will work). The idea is that it advances toward the opponent while staying in its blind spot. When it is close enough (3 cells away) it places itself in the diagonal of the opponent and shoots a missile.

import sys

def position(arena, element):
    y = [i for i,j in enumerate(arena) if element in arena[i]][0]
    x = arena[y].index(element)
    return (x,y)

def distance(other):
    dM = [[0 for x in range(10)] for y in range(10)]
    for i in range(len(dM)):
        for j in range(len(dM[0])):
            dM[i][j] = max([abs(other[0]-i),abs(other[1]-j)])
    return dM

def direction(coord1, coord2):
    d0 = coord1[0]-coord2[0]
    d1 = coord1[1]-coord2[1]
    if d1!=0:
        a = ['N','S'][d1<0]
    else: a = ""
    if d0!=0:
        b = ['W','E'][d0<0]
    else: b = ""
    return a+b

def getPath(coord, aim, speed):
    d = {'N': (0,-1), 'S':(0,1), 'E':(1,0), 'W':(-1,0), 'NW':(-1,-1), 'NE':(1,-1), 'SW':(-1,1), 'SE':(1,1)}
    D = d[aim]
    path = [(coord[0]+D[0]*i, coord[1]+D[1]*i) for i in range(speed+1)]
    return path

def dangerMap(stuff,other):
    dM = [[0 for x in range(10)] for y in range(10)]
    surroundings = [(other[0]+i,other[1]+j) for i in range(-2,3) for j in range(-2,3)]
    for i in range(len(dM)):
        for j in range(len(dM[0])):
            if i == other[0] : dM[i][j] = 1
            if j == other[1] : dM[i][j] = 1
            if (i,j) in [(other[0]+k, other[1]+k) for k in range(-10,11)]: dM[i][j] = 1
            if (i,j) in [(other[0]-k, other[1]+k) for k in range(-10,11)]: dM[i][j] = 1
    for j in surroundings:
        dM[j[0]][j[1]] = 2
    if len(stuff):
        s = [i.split(" ") for i in stuff]
        for i in s:
            if i[0]=='L':
                g = [(int(i[1]),int(i[2]))]
            if i[0]=='M':
                g = getPath((int(i[1]),int(i[2])),i[3],2)
            if i[0]=='B':
                g = getPath((int(i[1]),int(i[2])),i[3],3)
            for j in g:
                dM[j[0]][j[1]] = 2
    return dM

input = sys.argv[1].splitlines()
arena = input[0:10]
stuff = input[12:]
me = position(arena, "Y")
other = position(arena,"X")
distOther = distance(other)
distMe = distance(me)
dangM = dangerMap(stuff,other)
if distOther[me[0]][me[1]] > 3:
    surroundings = [(i,j) for i in range(10) for j in range(10) if distMe[i][j]==1]
    choice = [k for k in surroundings if dangM[k[0]][k[1]] == 0]
    if len(choice)==0: choice = [k for k in surroundings if dangM[k[0]][k[1]] == 1]
    if len(choice)>1:
        K = []
        for i in choice: K += [distOther[i[0]][i[1]]]
        choice = [choice[k] for k in range(len(choice)) if K[k] == min(K)]
    action = direction(me,choice[0])
else:
    diag = [(other[0]+i, other[1]+i) for i in [-2,2]]+[(other[0]-i, other[1]+i) for i in [-2,2]]
    if me in diag:
        action = 'M '+direction(me,other)
    else:
        distDiag = []
        for i in diag:
            distDiag += [distMe[i[0]][i[1]]]
        choice = [diag[k] for k in range(len(diag)) if distDiag[k] == min(distDiag)]
        action = direction(me,choice[0])

sys.stdout.write(action)