Two roads diverged in a yellow wood (part 1)

Question

This is the first in a series, the second is Two roads diverged in a yellow wood (part 2)

This challenge is inspired by Robert Frost's famous poem, "The Road Not Taken":

Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveler, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;

Then took the other, as just as fair,
And having perhaps the better claim,
Because it was grassy and wanted wear;
Though as for that the passing there
Had worn them really about the same,

And both that morning equally lay
In leaves no step had trodden black.
Oh, I kept the first for another day!
Yet knowing how way leads on to way,
I doubted if I should ever come back.

I shall be telling this with a sigh
Somewhere ages and ages hence:
Two roads diverged in a wood, and I —
I took the one less traveled by,
And that has made all the difference.

Notice the second to last line, I took the one less traveled by,.

Your actual challenge

You will take input in the form like:

#     ##
 #   ##
  # ##
   #
   #
   #

and you have to find the thinner road.

The road starts at the bottom with a #. The other 2 roads, which always terminate on the top row, are the roads you have to examine. The road that is the thickest is most traveled by, and therefore it is not what you want. The other one is the least traveled by, and it is the one you want.

Output

Your program/function must output one of 2 distinct values (eg. 0 or 1, true or false), one for each possible position of the road not taken. For example, you could output 0 if the road not taken is on the left of the road taken, and 1 otherwise, or you could output the string "left" or "right", true, false, etc.

Test cases:

 ##    #
  ##  #
   ###
    #
    #
    #

Might output "right".

 ##  #   
  ## #  
   ###
    ##
     #
     #
     #

Might output "right".

 ##  #   
  ## #  
   ###
    ##
   # 
  #  
 #   

Might output "right".

 ##   #  
  ## #  
   ###
    #
   # 
  #  
  #  

Might output "right".

 #    ## 
  #  ## 
   ###
    #
   # 
  #  
  #  

Might output "left"

 #    ## 
  #  ## 
   ###
    #
     #
     #
     #

Might output "left"

Notes

• This is code-golf, so the shortest answer in bytes wins
• Standard loopholes forbidden
• You must specify your outputs for "left" and "right" and they must be distinct
• Input will be one big string, and may have any amount of lines
• You don't need to worry about valid input.
• The road is always a Y shape, so you only have to look at the top.
• Have any questions? Comment below:

Lowest byte count wins!

Answer 1

CJam, 1 byte

r

r puts the first string of adjacent non-whitespace characters from STDIN on the stack, so this prints ## for left and # for right.

Try it online!

Answer 2

JavaScript(ES6), 19 12 bytes

Edit:

A more golfed version is

a=>a.trim[1]

Returns # for right and a space for left.

Original:

a=>a.trim()[1]=='#'

Explanation

Ungolfed:

function(input) {
  return input.trim().charAt(1) === '#';
};

The first thing this function does is remove white space the beginning and end of the input. This means that the first character is always #. Then from there I check the second character(JavaScript starts at 0) and see if it is a # character. This returns a boolean. If the path is right it will be true, if it is left it will return false.

How I golfed it

In ES6 there is an anonymous function shorthand called an arrow function. This means that I can take my wrapper function and turn it into:

input => ...;

Due to the rules of arrow functions it will return the rest of the code. From there I converted charAt(1) to [1] as it is a shorter way, though not recommended. Then I took === and turned it into ==. While they are different in this case it doesn't matter. Finally, I renamed input to a and removed all whitespace.

Output right and left

While the puzzle doesn't actually need the program to output right and left, here's an example of other outputs:

a=>a.trim()[1]=='#'?'right':'left'

The only added part is ?'right':'left'. This creates a ternary operator, a condensed if statement, this means that the(ungolfed) code is equal to*:

function(input) {
  let output = input.trim().charAt(1) === '#';
  if(output) {
    return 'right';
  } else {
    return 'left'
  }
};

Example

// Function assignment not counted in byte count
let f =
a=>a.trim()[1]=='#'

<textarea placeholder="Put path in here" id="path" rows="10" style="width:100%"></textarea>
<button onclick="document.getElementById('result').textContent = f(document.getElementById('path').value)">Submit</button>
<p id="result"></p>

Answer 3

Pyth, 2 bytes

hc

Outputs # for left and ## for right.

Try it online

Explanation

hc
 cQ     Split the (implicit) input on whitespace.
h       Get the first part.

Answer 4

Acc!!, 30 bytes

Because of the way Acc!! takes input, it will give the output after just one line of input is entered. But if you pipe the input in or redirect it from a file, you shouldn't notice the difference.

Count i while 35-N {
}
Write N

Takes input from stdin. Outputs if the left-hand road is less traveled, or # if the right-hand road is less traveled. Try it online!

Explanation

N reads the ASCII value of a character from stdin every time it is referenced. We loop while 35-N is truthy; that is, while 35-N != 0 or N != 35. Therefore, when the loop exits, we have just read the first # character on the line. The next character is then read with N and written back to stdout with Write.

Answer 5

Retina, 5 bytes

Outputs 1 if right, 0 if left.

^ *##

Try it online

---

If the values for a positive result didn't have to be distinct (5 bytes):

Outputs a positive integer if right, zero if left.

## +#

Try it online

Answer 6

IBM/Lotus Notes Formula Language, 37 35 26 bytes

Edit I always forget that @Like with wildcards is 2 bytes cheaper than @Contains.

Edit 2 Actually doesn't need the @if as it just prints 1 or 0 depending on whether the formula results to @True or @False.

@Like(@Left(a;"##");"%#%")

Computed field formula. Simply take everything to the left of the first ## it finds in field a and if there is a # in it outputs 1 for left otherwise outputs 0 for right.

With thanks to @DavidArchibald, here is a solution for 22 bytes. Out of respect for Davids solution I won't post it as my main answer.

@Left(@Trim(a);2)="##"

This one outputs 1 for right and 0 for left.

Answer 7

Pip, 8 6 bytes

a~`#+`

Takes input as a command-line argument (which will need quoting and escaping of newlines when run from an actual command line). Outputs # if the left-hand road is less traveled, and ## if the right-hand road is less traveled. Try it online!

Explanation

This uses Pip's recently added regex first-match operator.

a         First cmdline arg
 ~        Regex match the first instance of...
  `#+`    ...one or more #s (i.e. a cross-section of the left-hand road)
          Print (implicit)

The straightforward regex solution (a port of mbomb007's Retina answer) is 9 bytes:

`^ +##`Na

Answer 8

Chip, 7 bytes

AZ~S
at

Try it online!

Outputs 0x0 for left, and 0x1 for right. (The TIO includes flag -v so you can see the binary values in stderr. To see the output in ASCII, e*f can be appended to the end of the first line.)

Chip operates on individual bits within a byte stream, which actually makes it quite good at this specific problem.

A is the least significant bit of the input byte, and '#' is the only character of input for which this bit is set. When this bit is first encountered, we have reached the first '#' of the first line.

Z delays that signal for one cycle, so that we are now looking at the next character.

t is now activated, which means to terminate execution after this cycle is completed. We don't need to look further than the width of the first road.

~S suppresses output for all cycles except the final one. If this wasn't here, we'd get an output on every cycle.

a puts the current value of its neighbors (only A in this case) to the least significant bit of the output byte.

All of this means that we get a 0x1 if the first '#' is immediately followed by another '#', and 0x0 otherwise.

Answer 9

C, 35 bytes

f(char*s){while(35^*s++);return*s;}

Same idea as PragmaticProgrammer's answer: find the first #, and output what comes after it -- # for "right", and <space> for "left".

C (loophole), 16 bytes

According to the test cases, it looks like the left road is always exactly one space from the left margin. So...

#define f(s)2[s]

Answer 10

Batch, 46 bytes

@set/ps=
@for %%a in (%s%)do @echo %%a&exit/b

Reads one line from STDIN, splits it on spaces, and prints out the first word, so outputs # for left and ## for right. If an array of quoted command-line parameters is acceptable, then for 36 bytes:

@for %%a in (%~1)do @echo %%a&exit/b

Unquotes the first argument so that it will be split on spaces and print its first word.

Answer 11

Python 2, 21 bytes

Try it online

lambda S:S.split()[0]

Output # for left and ## for right

Answer 12

Haskell, 21 bytes

f n=snd$span(==' ')n!!1

or in point-free style:

(!!1).snd.span(' '==)

"#" means right, and " " means left

The function just takes a string, drops the beginning spaces, and then, it takes the second character (space if the left is skinny and # if the left is thick)

EDIT: Saved three bytes thanks to Laikoni and nimi!

Answer 13

Retina, 5 bytes

!1`#+

Try it online!

An alternative 5-byte solution. Prints # for left and ## for right. The idea is to match all the runs of #s (#+) and print (!) only the first one of them (1).

Answer 14

Brainfuck, 32 bytes

+[>,>+++++[<------>-]<--[,.>>]<]

Ungolfed:

+[                       while 1
>,>+++++[<------>-]<--     3 if hash; 0 if space
[,.>>]                     print next char and break iff current char is hash
<]

Prints # for right and for left.

Try it online!

Answer 15

C 54 bytes

char*strchr();char c(char*s){return*(strchr(s,35)+1);}

C++ 58 bytes

#include<cstring>
char c(char*s){return*(strchr(s,35)+1);}

Since OP specified it can be a "program/function" I elected to write a function to save characters. However, I still included the "#include" statement and accompanying line break in the character count as they are required to compile the function.

Output

Returns a space " " character to indicate left, or a hash "#" character to indicate right.

Explanation

The strchr() function walks a given string and returns a pointer to the first occurrence of a specified character. It has an overload which accepts an integer as the second argument as opposed to a char which saves me 1 character. E.g. '#' can be replaced with 35. I then add one to the pointer returned from the function to get the character immediately following, and dereference it, then return the resulting char.

Note

I would also like to take this opportunity to formally express my annoyance at Visual Studio auto-formatting my code when I'm trying to golf (╯°□°）╯︵ ┻━┻.

Edit: Thanks to Ray for pointing out some differences in C and C++ and where I could save characters <3.

Answer 16

Perl 5, 8 + 1 = 9 bytes

die$F[0]

Try it online!

Run with -a (1 byte penalty).

Output is # at filename line 1, <> line 1 (where filename is the filename of the script) if the left road is less travelled, or ## at filename line 1, <> line 1 if the right road is less travelled.

Explanation

The -a option automatically reads input and splits it into columns around whitespace, ignoring leading whitespace. As such, the first datum of input is what we need; that's $F[0]. It also puts the program in an implicit loop, which we don't want. However, the use of die allows us to output a string, and exit the implicit loop, at the same time (and with no more characters than say, the more usual way to print a string).

Answer 17

JavaScript (ES6), 37 bytes

p=s=>/^ *#( |$)/.test(s.split("\n")[0])

Explanation:

p is a function that returns true if the road less traveled by is on the left and false otherwise. This is my first answer on this site, so it probably could be golfed more (maybe the regex.)

It works by taking the top line of the input and seeing if it matches the regex /^ *#( |$)/ (start of string, any amount of spaces, a #, and a space or end of string.)

This is just to give people clarification about the format and generate ideas. I am sure it can be beat and golfed further. Happy golfing!

p=s=>/^ *#[^#]/.test(s.split("\n")[0])

<textarea rows = "8" cols = "8" oninput = "console.log(p(this.value))"></textarea>

Answer 18

Japt, 3 bytes

x

(2 bytes for -g1 flag) Outputs # for right and a space for left. Based on the JavaScript answer by David Archibald.

Try it online!

Answer 19

Excel, 17 bytes

=left(trim(A1),2)

Assumes input in cell A1.

Returns ## for right and # (# and space) for left.

Answer 20

Java 7, 166 66 63 52 43 bytes

int c(String s){return s.trim().charAt(1);}

Outputs 35 for right and 32 for left.
Based on @Clashsoft's Dyvil answer.

Explanation:

int c(String s){   // Method with String parameter and integer return-type
  return s.trim()  //  Remove leading and trailing whitspaces
   .charAt(1);     //  and return the second character (as int value)
}                  // End of method

Test code:

class M{
  static int c(String s){return s.trim().charAt(1);}

  public static void main(String[] a){
    System.out.println(c(" ##    #\n  ##  #\n   ###\n    #\n    #\n    #"));
    System.out.println(c(" ##  #   \n  ## #  \n   ###\n    ##\n     #\n     #\n     #"));
    System.out.println(c(" ##  #   \n  ## #  \n   ###\n    ##\n   # \n  #  \n #   "));
    System.out.println(c(" ##   #  \n  ## #  \n   ###\n    #\n   # \n  #  \n  #  "));
    System.out.println(c(" #    ## \n  #  ## \n   ###\n    #\n   # \n  #  \n  #  "));
    System.out.println(c(" #    ## \n  #  ## \n   ###\n    #\n     #\n     #\n     #"));
  }
}

Try it here.

Output:

35
35
35
35
32
32

Answer 21

Dyvil, 12 bytes

s=>s.trim[1]

Explanation:

s=>          // lambda expression
   s.trim    // removes leading (and trailing) whitespace
         [1] // gets the second character

Usage:

let f: String -> char = s=>s.trim[1]
print f('...')

Returns (whitespace) for left and # for right.

Answer 22

Befunge 98, 11 bytes

-!jv~'
@.~<

Try it Online!

Prints 32 for left, and 35 for right, both with a single trailing space.

Explanation

-!jv      This is a no-op the first time through, but used later

    ~'    Pushes the ASCII value of the next character, and pushes 32
-!        Subtracts the 2, and nots. If the character was a space, the top will be 1
  jv      Goes to the second line if the character was not a space

  ~<      Pushes the next characer's ASCII value
 .        Prints it (32 for " " and 35 for "#")
@         Ends the program

One trick I used was putting the -!jv first, even though it didn't do anything. This let me both get rid of the space after the ' and saved some padding. With this last, the code would be

~' -!jv
   @.~<

for 15 bytes.

Answer 23

Ruby, 20 bytes

->r{r.strip[1]==' '}

Returns true for left, false for right.