Print a random maze

Question

Write a program that generates and prints a random maze using the algorithm of your choice. The maze should be different for multiple runs of the program. Height and width are given as command line arguments. Use | for vertical wall, - for horizontal wall and + for corner. The maze is bounded by walls and the entrances are marked by missing wall. The maze contains a treasure # which must be reachable from at least one entrance.

$ python2 random-maze.py 4 5
+-+-+
  |#|
|   |
+---+

Answer 1

I think this technically isn't a maze generator, but it creates a maze like result: https://gist.github.com/803450.

Some horrible code in there I know, and it only works less than half the time, and the result doesn't look quite right to do with walls sticking out from other walls. But its close enough that I can't be bothered fixing the rest.

Some example output:

→ ruby random-maze.rb 30 30
+----+-+-----------++-+----+
|    + |           ++ |    |
++  +  | ++ ++   +    + ++ ++
|  ++ ++ |  |    +---+  +   |
| +      | +| +   +++  +  + |
|   +   +| +| +-+  |   + +  |
|        +  +    + + ++  |+ |
| + ++ +  ++   + |  +   ++| |
| |  | ++  + +----+ + +-+ | |
| +  |  +-+  |+        |  | |
|   +-+  +| ++  ++ + + |  | |
| ++   +  + |  ++|   + | ++ |
|  + + + +  +---++-+   +++  |
| +  |  +| +    |  ++   |   |
| | +++ +| + ++ +--+  + |---+
|#+ | |  |   +++     +  +   |
++  | ++ +-+  ++ +--+  +  + |
|  ++  |    +     ++| +  ++ |
| ++   +--------+  +| + +   |
| |     |      +++  |  +  +-+
| |     | +--+  |++ |+ | ++
| |     |  +--+ | | || |  |
| |     +-+     +-+ |+ |+ |
| | +---+   ++      +  |  |
| +-|     +    +      ++ ++
|   +       ++   +---+   |
|              ++   +  +-+
|                 +   ++
+-+ +-------------+---+

Answer 2

Python, 375 characters

import random,sys
H,V=map(int,sys.argv[1:])
H-=1
V-=1
b,h,v,p=' -|+'
M=H/2*h
n=random.randint(1,(H/2)*(V/2-1))
for i in range(V/2):
 e=s=t='';N=v
 for j in range(H/2):
  if i and(random.randint(0,1)or j==0):s+=N+b;t+=v;N=v;M=M[1:]+p
  else:s+=M[0]+h;t+=b;N=p;M=M[1:]+h
  n-=1;t+=' #'[n==0]
 if H&1:s+=s[-1];t+=b;e=h
 print s+N+'\n'+t+v
if V&1:print t+v
print h.join(M)+e+h+p

This generates a maze with one entrance and a randomly placed treasure. The maze is a simple binary tree maze.

$ ./maze.py 15 15
--------------+
              |
| | ----------+
| |           |
| +-----+ | --+
|       | |   |
| --+ --+ +---+
|   |   |     |
| --+-+ +---+ |
|     |     | |
| --+ +-+ --+ |
|   |   |   |#|
| | | --+ --+-+
| | |   |     |
+-+-+---+-----+

Answer 3

Ruby 1.9.2p136 : 90

eval ARGV[0]
z=[l="+"+"-"*@w+"+"]
@h.times{z<<"|"+" "*@w+"|"}
z[rand(@h)+1]="|#"
puts z<<l

Output

$> ruby maze.rb "@h=8;@w=8;"

+------+
|      |
|      |
|      |
|      |
|#
|      |
+------+

Hey, no one said it had to be a good maze. OK, OK, I'll make a real one now.

Answer 4

C 844

#include <stdlib.h>
#include <time.h>
h,w,*m,y,x,z;d(t,b,l,r){int i=b-t,j=r-l;if(i>1&&j>1){i=(rand()%--i)|1;j=(rand()%--j)|1;z=rand()%4;x=rand()%i+t;x|=1;for(y=t;y<i+t;y++)if(y!=x||!z)m[y*w+j+l]=124;x=rand()%(b-i-t)+i+t;x|=1;for(y=t+i;y<b+1;y++)if(y!=x||!(z-1))m[y*w+j+l]=124;y=rand()%j+l;y|=1;for(x=l;x<j+l;x++)if(y!=x||!(z-2))m[(i+t)*w+x]=45;y=rand()%(r-j-l)+j+l;y|=1;for(x=l+j;x<r+1;x++)if(y!=x||!(z-3))m[(i+t)*w+x]=45;m[(i+t)*w+j+l]=43;m[(t-1)*w+l+j]=43;m[(b+1)*w+j+l]=43;m[(i+t)*w+l-1]=43;m[(i+t)*w+r+1]=43;d(t,t+i-1,l,l+j-1);d(t+i+1,b,l,l+j-1);d(t,t+i-1,l+j+1,r);d(t+i+1,b,l+j+1,r);}}main(int c,char**v){h=atoi(v[1]),w=atoi(v[2]),m=calloc(h*w,4);srand(time(0));while(y<h){while(x<w){m[y*h+x]=(!y||y==h-1)?(!x||x==w-1)?43:45:(!x||x==w-1)?124:32;x++;}y++;x=0;}d(1,h-2,1,w-2);z=rand()%(w-2);z|=1;m[z]=32;z=rand()%(w-2);z|=1;m[h*(w-2)+z]=35;}

To Test:

#include <stdio.h>//beginning
for(y=0;y<h;y++){for(x=0;x<w;x++){putchar(m[y*h+x]);}putchar('\n');}getchar();//end

3x3

+ +
|#|
+-+

7x8

+-+-- -+
|      |
+ +-+--+
|      |
| +-+ -+
| |  # |
+-+-+--+

18x20

+-+-+ +---+---+-+--+
| | |         |    |
| + + +-- +---+ +--+
|     |       |    |
+ + +-+---+-- +-+ -+
| |   |            |
+-+ +-+-+-+---+-+--+
| | |   |       |  |
| + + + +-+-- --+  |
| |   |         |  |
| | | +-+-+ ----+  |
|   | |         |  |
+ + +-+-+-+-- --+ -+
| |   |         |  |
| + +-+-- +-- --+  |
| |   |   |        |
| | | |  #|     |  |
+-+-+-+---+-----+--+

Answer 5

Here's a simple java solution:

import java.util.*;

public class MazeGen {
    public static void main(String[]a){
        int w,l;
        Random rand=new Random(System.currentTimeMillis()%1000+System.nanoTime());
        if(a.length==2){
            w=Integer.parseInt(a[0]);
            l=Integer.parseInt(a[1]);
        }else{
            System.out.println("No command line arguments, taking from STDIN.");
            Scanner input=new Scanner(System.in);
            w=input.nextInt();
            l=input.nextInt();
            input.close();
        }
        char[][]maze=new char[w][l];
        for(int x=0;x<w;x++){
            for(int y=0;y<l;y++){
                maze[x][y]=' ';
            }
        }
        for(int x=0;x<w;x++){
            maze[x][0]=maze[x][l-1]='|';
        }
        for(int y=0;y<l;y++){
            maze[0][y]=maze[w-1][y]='-';
        }
        maze[0][0]=maze[w-1][0]=maze[w-1][l-1]=maze[0][l-1]='+';
        int dor=1+rand.nextInt(l-2);
        maze[0][dor]=' ';
        int tx=2+rand.nextInt(w-3),ty=1+rand.nextInt(l-2);
        maze[tx][ty]='#';
        if(ty<dor-1){
            maze[tx][ty+1]='|';
            if(tx==w-2){
                maze[tx+1][ty+1]='+';
            }
            if(tx==1){
                maze[0][ty+1]='+';
            }
        }
        if(ty>dor+1){
            maze[tx][ty-1]='|';
            if(tx==w-2){
                maze[tx+1][ty-1]='+';
            }
            if(tx==1){
                maze[0][ty-1]='+';
            }
        }
        if(ty==dor&&tx>3&&(maze[tx][ty+1]==' '||maze[tx][ty-1]==' ')){
            maze[tx-1][ty]='-';
        }
        if(dor>5){
            int z=2+rand.nextInt(dor-3);
            int q=1+rand.nextInt(w-3);
            for(int i=0;i<w;i++){
                if(i==0||i==w-1){
                    maze[i][z]='+';
                }else if(i!=q&&maze[i][z]==' '){
                    maze[i][z]='|';
                }
            }

        }
        if(l-dor>5){
            int z=dor+2+rand.nextInt(l-dor-3);
            int q=1+rand.nextInt(w-3);
            for(int i=0;i<w;i++){
                if(i==0||i==w-1){
                    maze[i][z]='+';
                }else if(i!=q&&maze[i][z]==' '){
                    maze[i][z]='|';
                }
            }

        }
        for(char[]row:maze){
            System.out.println(row);
        }
    }
}

Some sample results:

3x3:

+ +
|#|
+-+

4x4:

+ -+
| #|
|  |
+--+

4x5:

+-+ +
|#| |
|   |
+---+

5x5:

+ --+
|   |
|   |
| |#|
+-+-+

5x8:

+ --+--+
|   |  |
|      |
| # |  |
+---+--+

8x15:

+---- ----+---+
|         |   |
|         |   |
|         |   |
|             |
| #|      |   |
|         |   |
+---------+---+