Build a checkerboard

Question

For this challenge you will print the coordinates and color of each piece at the start of a game of checkers.

Enter the x and y (comma seperated) for every square (indexed 0-7) on a checkerboard, followed by a "r" or "b" (for red or black) where the top of the board (closer to y=0) is red and the bottom is black. newlines between pieces are required and no spaces are necessary.

This is code-golf so answers are scored in bytes with fewer bytes being better.

Trailing newlines are allowed but not necessary and the order must be exactly of that below.

Desired output:

0,0r
0,2r
0,4r
0,6r
1,1r
1,3r
1,5r
1,7r
2,0r
2,2r
2,4r
2,6r
5,1b
5,3b
5,5b
5,7b
6,0b
6,2b
6,4b
6,6b
7,1b
7,3b
7,5b
7,7b

Answer 1

05AB1E, 26 bytes

2ÝD5+«v4Fy',N·yÉ+„bry3‹èJ,

Try it online!

Explanation

2Ý                           # push [0,1,2]
  D5+                        # duplicate and add 5: [5,6,7]
     «                       # concatenate
      v                      # for each y in [0,1,2,5,6,7] do:
       4F                    # for each N in [0 ... 3] do:
         y                   # push y
          ',                 # push ","
            N·yÉ+            # push N*2+isOdd(y)
                 „br         # push "br"
                    y3‹è     # index into the string with y<3
                        J,   # join everything to a string and print

Answer 2

JavaScript (ES6), 66 bytes

Includes a trailing newline.

f=(n=24)=>n--?f(n)+[2*(x=n>11)+(y=n>>2),n%4*2+y%2+'rb'[+x]]+`
`:''

Demo

f=(n=24)=>n--?f(n)+[2*(x=n>11)+(y=n>>2),n%4*2+y%2+'rb'[+x]]+`
`:''

console.log(f())

Answer 3

Perl 5, 53 bytes

//&map{say"$',",$_+$'%2,$'<4?r:b}0,2,4,6for 0..2,5..7

Try it online!

Answer 4

C (gcc), 83 81 79 78 bytes

• Saved two bytes thanks to Tahg; golfing x/4+2*(x/12) to x/4+x/12*2.
• Saved two bytes thanks to Kevin Cruijssen; golfing x%8*2%8 to x*2%8.
• Saved a byte thanks to ceilingcat.

x;main(){for(;x<24;)printf("%d,%d%c\n",x/4+x++/12*2,x*2%8+x/4%2,114-x/12*16);}

Try it online!

Answer 5

Python 2, 74 73 67 bytes

for i in 0,1,2,5,6,7:j=i%2;exec"print`i`+','+`j`+'rb'[i>4];j+=2;"*4

Try it online!

Answer 6

Java 8, 102 96 95 93 91 bytes

v->{for(int i=0;i<24;System.out.printf("%d,%d%c%n",i/4+i/12*2,i*2%8+i/4%2,i++<12?114:98));}

Port from @JonathanFrech's C answer, after which I golfed 5 bytes myself.

Try it here.

Explanation:

v->{                    // Method without empty unused parameter and no return-type
  for(int i=0;i<24;     //  Loop from 0 to 24 (exclusive)
    System.out.printf("%d,%d%c%n",
                        //   Print with format:
                        //   (%d=digit; %c=character; %n=new-line)
      i/4+i/12*2,       //    Print first coordinate
      i*2%8+i/4%2,      //    Print second coordinate
      i++<12?114:98)    //    Print either 'r' or 'b'
  );                    //  End of loop
}                       // End of method

Answer 7

Bash, 59 bytes

Not the shortest, but a fun one:

printf %s\\n {{0,2,6}\,{0,2,4,6}r,{1,5,7}\,{1,3,5,7}b}|sort

Try it online!

Answer 8

APL (Dyalog Classic), 38 bytes

(⍕⍪4/3 4~⍨⍳8),',',(⍕⍪24⍴⍋8⍴⍳2),12/'rb'

Try it online!

Answer 9

Jelly, 35 bytes

8Ḷḟ3ḟ4µḂr7m2ṭ€µ€Ẏµḣ1<3Ḣị⁾rbṭj”,$µ€Y

Try it online!

Full program taking no arguments

Explanation

8Ḷḟ3ḟ4µḂr7m2ṭ€µ€Ẏµḣ1<3Ḣị⁾rbṭj”,$µ€Y  Main link; no arguments
8                                    8
 Ḷ                                   Push 0 .. 8 - 1
  ḟ                                  Remove all instances of
   3                                 3
    ḟ                                Remove all instances of
     4                               4
                €                    For each in [0, 1, 2, 5, 6, 7]
       µḂr7m2ṭ€µ                     Generate all of the piece coordinates across that row
        Ḃ                            row number % 2
         r                           inclusive range up to
          7                          7
           m                         modular; take every   elements
            2                                            2
              €                      For each column coordinate
             ṭ                       Tack the row coordinate (reverse append)
                 Ẏ                   Tighten; flatten once
                                 €   For each piece coordinate (in the right order now)
                 µḣ1<3Ḣị⁾rbṭj”,$µ    Convert to its final output
                  ḣ                  Head; take the first   element(s)
                   1                                      1
                    <                Less Than; compare each element to
                     3               3
                      Ḣ              Head; take the comparison out of the list
                       ị             Index (1-indexed) into
                        ⁾rb          "rb"
                           ṭ         Tack the color character behind
                            j”,$     The coordinates joined by a comma
                            j        Join with separator
                             ”,      ","
                                  Y  Separate by newlines

Answer 10

Java 8, 97 bytes

o->{int i=0,g;for(;i<8;i+=i==2?3:1)for(g=i%2;g<8;g+=2)System.out.println(i+","+g+(i<5?"r":"b"));}

Answer 11

JavaScript (ES6), 64 bytes

This seems sufficiently different from @Arnauld's to warrant posting:

f=(n=0,y=n>>3,c=y>2)=>y<6?[y+c*2,n%8+y%2+'rb'[+c]]+`
`+f(n+2):''

Explanation:

f=(n = 0,            //the numbered square on checkerboard
   y = n >> 3,       //current row (n / 8 rounded)
   c = y > 2         //false if red pieces, true if black
  ) => 
  y < 6 ?            //if y less than 6 
    [                //  using an array automatically adds the comma
     y + c * 2,      //  0 - 2 if red pieces, 5 - 7 if black
     n%8 + y%2 +     //  n%8 returns 0, 2, 4, or 6.
                     //  y%2 returns 0 or 1.
                     //  added, they return the appropriate position (0 - 7)
     'rb'[+c]        //  'r' if red, 'b' if black.  Plus sign coerces boolean to number.
    ]+`              //  new line
    `+
    f(n+2) :         //  recurse on n+2
    ''               //else return an empty string

Snippet:

f=(n=0,y=n>>3,c=y>2)=>y<6?[y+c*2,n%8+y%2+'rb'[+c]]+`
`+f(n+2):''

console.log(f());

Answer 12

Python 2, 63 bytes

x=0;exec"print`x/8+x/24*2`+','+`x%8+x/8%2`+'rb'[x/24];x+=2;"*24

Try it online!

Answer 13

APL (Dyalog), 45 44 bytes*

-1 thanks to ngn.

Niladic function which assumes 0-based indexing (⎕IO←0) which is default on many systems. Prints to STDOUT.

↑' '⎕R','⊃,/(8 ¯8↑¨⊂⍕¨⍸∘.=⍨2|⍳8),¨¨'rb'

Try it online!

(…),¨¨'rb' append "r" to each of the first group of items and "b" to each of the second:

 ⍳8 zero through eight

 2| division remainder when halved

 ∘.+⍨ plus table with itself on along both axes

 ⍸ indices of true values

 ⍕¨ format each (converts to strings with the pattern d d where each d is a digit)

 ⊂ enclose (so we can reuse it for each…)

 8 ¯8↑¨ take the first nine and the last nine

now we have two lists of d d strings

,/ catenation reduction (combine the two lists)

⊃ disclose (because the reduction reduced the rank from 1 to 0)

' '⎕R',' PCRE Replace spaces with commas

↑ mix (the all the lists into a single matrix)

---

^{* In Dyalog Classic, counting ⍸ as ⎕U2378.}

Answer 14

Bubblegum, 59 bytes

00000000: 15ca b101 0030 0400 c1de 2c0a 2462 1f23  .....0....,.$b.#
00000010: d8bf 886f ae3a 531b 310d b8f0 465c 1d0e  ...o.:S.1...F\..
00000020: 24d4 48ec 5b02 2eec 4bf5 5e0e 2454 cb53  $.H.[...K.^.$T.S
00000030: 8380 0baf a5d4 e140 42f5 07              .......@B..

Try it online!

Answer 15

Pyth, 37 36 35 bytes

isaacg wouldn't be proud

V+U3}5 7FG4p++N\,+yG?!%N2Z1?<N5\r\b

Explanation:

V+U3}5 7            For in the array [0, 1, 2, 5, 6, 7] as N
 FG4                 For in the array [0, 1, 2, 3] as G
  p                   Print without newline:
   ++N\,+yG?!%N2Z1     N, (2 * G) + 1 if N is even, else 0
  ?<N5\r\b            Output with newline "r" if N < 5 else "b"

This uses a simple pattern I cut down a bit. As follows:

If the X coord is even, use the even numbers 0, 2, 4, 6. Else, 1, 3, 5, 7 for Y.

If the X coord is less than 5, the color (r or b) is r. Else, it is b.

Try it online!

edit: overnight got +40 rep on 3 different answers w00t

Answer 16

SOGL V0.12, 31 bytes

⁰¹²⁵⁶⁷’{A4∫«Ha2\⌡HaOļ,pƧbra4>Wo

Try it Here!

Answer 17

Javascript (89 bytes):

for(x=y=0,r="r";x<7|y<8;console.log(x+","+y+r),y+=2){if(y>7)y=++x%2;if(x==3){x+=2;r="b"}}

Readable:

for(var x = y = 0, red = true; x < 7 || y < 8; y += 2) {
    if(y > 7) { //new row
        x++;
        y = x % 2;
    }
    if(x == 3) { //new color
        x += 2;
        red = false;
    }
    console.log(x + "," + y + (red ? "r" : "b") );
}

Try it online!

Answer 18

Jelly, 27 bytes

8Ḷµḟ3,4pµSḂ$Ðḟj€”,ż⁾rbx12¤Y

A full program which prints the required output.

Try it online!

How

8Ḷµḟ3,4p⁸SḂ$Ðḟj€”,ż⁾rbx12¤Y - Link: no arguments
8                           - literal eight
 Ḷ                          - lowered range = [0,1,2,3,4,5,6,7]
  µ                         - new monadic chain
    3,4                     - literal list = [3,4]
   ḟ                        - filter discard = [0,1,2,5,6,7]
        ⁸                   - chain's left argument = [0,1,2,3,4,5,6,7]
       p                    - Cartesian product = [[0,0],[0,1],...,[2,7],[5,0],...,[7,6],[7,7]]
            Ðḟ              - filter discard if:
           $                -   last two links as a monad:
         S                  -     sum
          Ḃ                 -     modulo by 2
                ”,          - literal comma character
              j€            - join €ach pair with a comma = [0,',',0],[0,',',2],...,[2,',',6],[5,',',1],...,[7,',',5],[7,',',7]]
                         ¤  - nilad followed by links as a nilad:
                   ⁾rb      - literal list = ['r','b']
                       12   - literal twelve
                      x     - repeat = ['r','r','r','r','r','r','r','r','r','r','r','r','b','b','b','b','b','b','b','b','b','b','b','b']
                  ż         - zip together = [[[0,',',0],'r'],[[0,',',2],'r'],...,[[2,',',6],'r'],[[5,',',1],'b'],...,[[7,',',5],'b'],[[7,',',7],'b']]
                          Y - join with newlines = [[0,',',0],'r','\n',[0,',',2],'r','\n',...,'\n',[2,',',6],'r','\n',[5,',',1],'b','\n',...,'\n',[7,',',5],'b','\n',[7,',',7],'b']
                            - implicit print (smashes the list of lists and characters
                            -                 together and prints the digits)

Answer 19

Ruby, 63 60 bytes

[*0..11,*20..31].map{|x|puts [x/4,2*x%8+x[2]]*?,+"rb"[x[4]]}

Bitmask magic saves the byte.

Try it online!

Answer 20

PowerShell, 63 bytes

0..2+5..7|%{$i=$_;0,2,4,6|%{"$i,$($_+$i%2)"+('r','b')[$i-ge5]}}

Try it online!

Loops over 0,1,2,5,6,7 and each iteration sets $i to the current number. Then loops over 0,2,4,6. Each inner loop, we construct a string starting with $i, then concatenated with our inner loop's current number plus whether $i is even or odd (which gets us 0,2,4,6 one time and 1,3,5,7 the other time), then concatenated with either red or black based on whether $i is -greater-than-or-equal to 5. Those strings are all left on the pipeline and the implicit Write-Output at program completion gives us newlines for free.

Answer 21

J, 48 44 40 37 31 bytes

(}:"1":$.|:8$#:162 69),.12#'rb'

Try it online!

How it works

           8$#:162 69    first 2 columns in binary, take 8 of them
         |:              transpose
       $.                format as a sparse array, kind of looks like the goal
     ":                 "to text"
 }:"1                    delete the last column
       ,.12#'rb'         append 12 rs followed by 12 bs as the last column

Answer 22

C# (.NET Core), 96 bytes

()=>{for(int i=0;i<24;)System.Console.Write($"{i/4+i/12*2},{i*2%8+i/4%2}{(i++>11?"b":"r")}\n");}

Try it online!

Essentially just a port to C# of @JonathanFrech's answer. I couldn't come up with any better way of doing the math.