Connect 4: Spot the Fake!
$begingroup$
The bank has been broken into, and all the local mafia thugs have an unusual alibi: they were at home playing Connect 4! In order to assist with the investigation, you are asked to write a program to validate all the Connect 4 boards that have been seized in order to check that the positions are indeed positions from a valid Connect 4 game, and have not been hastily put together as soon as the police knocked on the door.
For example (with R starting), the following is an impossible Connect 4 position.
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | |
| | |Y| | | | |
|R| |Y| | | | |
Your program or function must take in a Connect 4 board and return either
- A falsy value, indicating that the position is impossible or
- A string of numbers from 1 to 7, indicating one possible sequence of moves leading to that position (the columns are numbered
1to7from left to right, and so the sequence112, for example, indicates a red move in column1, followed by a yellow move in column1, followed by a red move in column2). You may choose a column-numbering other than 1234567 if you like, as long as you specify in your solution. If you want to return the list in some other format; for example as an array[2, 4, 3, 1, 1, 3]then that is fine too, as long as it is easy to see what the moves are.
You can choose to read the board in in any sensible format including using letters other than R and Y for the players, but you must specify which player goes first. You can assume that the board will always be 6x7, with two players.
This is code golf, so shortest answer wins. Standard loopholes apply.
Examples
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> 1234567 (one possible answer)
| | | | | | | |
|R|Y|R|Y|R|Y|R|
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | | --> false
| | |Y| | | | |
|R| |Y| | | | |
| | | | | | | |
| | |Y| | | | |
| | |R| | | | |
| | |Y| | | | | --> 323333 (only possible answer)
| | |R| | | | |
| |Y|R| | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> false (this is the position arising after
| |Y|Y|Y|Y| | | the moves 11223344, but using those moves
| |R|R|R|R| | | the game would have ended once R made a 4)
code-golf board-game
asked 6 hours ago
John GowersJohn Gowers
1619
$endgroup$
add a comment |
$begingroup$
The bank has been broken into, and all the local mafia thugs have an unusual alibi: they were at home playing Connect 4! In order to assist with the investigation, you are asked to write a program to validate all the Connect 4 boards that have been seized in order to check that the positions are indeed positions from a valid Connect 4 game, and have not been hastily put together as soon as the police knocked on the door.
For example (with R starting), the following is an impossible Connect 4 position.
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | |
| | |Y| | | | |
|R| |Y| | | | |
Your program or function must take in a Connect 4 board and return either
- A falsy value, indicating that the position is impossible or
- A string of numbers from 1 to 7, indicating one possible sequence of moves leading to that position (the columns are numbered
1to7from left to right, and so the sequence112, for example, indicates a red move in column1, followed by a yellow move in column1, followed by a red move in column2). You may choose a column-numbering other than 1234567 if you like, as long as you specify in your solution. If you want to return the list in some other format; for example as an array[2, 4, 3, 1, 1, 3]then that is fine too, as long as it is easy to see what the moves are.
You can choose to read the board in in any sensible format including using letters other than R and Y for the players, but you must specify which player goes first. You can assume that the board will always be 6x7, with two players.
This is code golf, so shortest answer wins. Standard loopholes apply.
Examples
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> 1234567 (one possible answer)
| | | | | | | |
|R|Y|R|Y|R|Y|R|
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | | --> false
| | |Y| | | | |
|R| |Y| | | | |
| | | | | | | |
| | |Y| | | | |
| | |R| | | | |
| | |Y| | | | | --> 323333 (only possible answer)
| | |R| | | | |
| |Y|R| | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> false (this is the position arising after
| |Y|Y|Y|Y| | | the moves 11223344, but using those moves
| |R|R|R|R| | | the game would have ended once R made a 4)
code-golf board-game
asked 6 hours ago
John GowersJohn Gowers
1619
$endgroup$
$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the|, etc?
$endgroup$
– Jonah
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago
add a comment |
$begingroup$
The bank has been broken into, and all the local mafia thugs have an unusual alibi: they were at home playing Connect 4! In order to assist with the investigation, you are asked to write a program to validate all the Connect 4 boards that have been seized in order to check that the positions are indeed positions from a valid Connect 4 game, and have not been hastily put together as soon as the police knocked on the door.
For example (with R starting), the following is an impossible Connect 4 position.
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | |
| | |Y| | | | |
|R| |Y| | | | |
Your program or function must take in a Connect 4 board and return either
- A falsy value, indicating that the position is impossible or
- A string of numbers from 1 to 7, indicating one possible sequence of moves leading to that position (the columns are numbered
1to7from left to right, and so the sequence112, for example, indicates a red move in column1, followed by a yellow move in column1, followed by a red move in column2). You may choose a column-numbering other than 1234567 if you like, as long as you specify in your solution. If you want to return the list in some other format; for example as an array[2, 4, 3, 1, 1, 3]then that is fine too, as long as it is easy to see what the moves are.
You can choose to read the board in in any sensible format including using letters other than R and Y for the players, but you must specify which player goes first. You can assume that the board will always be 6x7, with two players.
This is code golf, so shortest answer wins. Standard loopholes apply.
Examples
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> 1234567 (one possible answer)
| | | | | | | |
|R|Y|R|Y|R|Y|R|
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | | --> false
| | |Y| | | | |
|R| |Y| | | | |
| | | | | | | |
| | |Y| | | | |
| | |R| | | | |
| | |Y| | | | | --> 323333 (only possible answer)
| | |R| | | | |
| |Y|R| | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> false (this is the position arising after
| |Y|Y|Y|Y| | | the moves 11223344, but using those moves
| |R|R|R|R| | | the game would have ended once R made a 4)
code-golf board-game
asked 6 hours ago
John GowersJohn Gowers
1619
$endgroup$
The bank has been broken into, and all the local mafia thugs have an unusual alibi: they were at home playing Connect 4! In order to assist with the investigation, you are asked to write a program to validate all the Connect 4 boards that have been seized in order to check that the positions are indeed positions from a valid Connect 4 game, and have not been hastily put together as soon as the police knocked on the door.
For example (with R starting), the following is an impossible Connect 4 position.
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | |
| | |Y| | | | |
|R| |Y| | | | |
Your program or function must take in a Connect 4 board and return either
- A falsy value, indicating that the position is impossible or
- A string of numbers from 1 to 7, indicating one possible sequence of moves leading to that position (the columns are numbered
1to7from left to right, and so the sequence112, for example, indicates a red move in column1, followed by a yellow move in column1, followed by a red move in column2). You may choose a column-numbering other than 1234567 if you like, as long as you specify in your solution. If you want to return the list in some other format; for example as an array[2, 4, 3, 1, 1, 3]then that is fine too, as long as it is easy to see what the moves are.
You can choose to read the board in in any sensible format including using letters other than R and Y for the players, but you must specify which player goes first. You can assume that the board will always be 6x7, with two players.
This is code golf, so shortest answer wins. Standard loopholes apply.
Examples
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> 1234567 (one possible answer)
| | | | | | | |
|R|Y|R|Y|R|Y|R|
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | |R| | | | | --> false
| | |Y| | | | |
|R| |Y| | | | |
| | | | | | | |
| | |Y| | | | |
| | |R| | | | |
| | |Y| | | | | --> 323333 (only possible answer)
| | |R| | | | |
| |Y|R| | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | |
| | | | | | | | --> false (this is the position arising after
| |Y|Y|Y|Y| | | the moves 11223344, but using those moves
| |R|R|R|R| | | the game would have ended once R made a 4)
code-golf board-game
code-golf board-game
asked 6 hours ago
John GowersJohn Gowers
1619
asked 6 hours ago
John GowersJohn Gowers
1619
edited 6 hours ago
John Gowers
asked 6 hours ago
John GowersJohn Gowers
1619
asked 6 hours ago
John GowersJohn Gowers
1619
asked 6 hours ago
John GowersJohn Gowers
1619
1619
$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the|, etc?
$endgroup$
– Jonah
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago
add a comment |
$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the|, etc?
$endgroup$
– Jonah
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago
$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the
|, etc?$endgroup$
– Jonah
4 hours ago
$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the
|, etc?$endgroup$
– Jonah
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
JavaScript (ES6), 202 188 bytes
Takes input as a matrix with $1$ for red, $2$ for yellow and $0$ for empty. Returns a string of 0-indexed moves (or an empty string if there's no solution). Reds start the game.
m=>(p=[...'5555555'],g=(c,s=o='')=>/1|2/.test(m)?[1,13,15,17].some(n=>eval(`/(5|6)(.{${n}}\1){3}/`).test(m))?o:p.map((y,x)=>m[(m[y][x]|=4)^c||p[g(c^3,s+x,p[x]--),x]++,y][x]&=3)&&o:o=s)(5)
Try it online!
answered 1 hour ago
ArnauldArnauld
73.6k689309
$endgroup$
add a comment |
Your Answer
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1 Answer
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1 Answer
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$begingroup$
JavaScript (ES6), 202 188 bytes
Takes input as a matrix with $1$ for red, $2$ for yellow and $0$ for empty. Returns a string of 0-indexed moves (or an empty string if there's no solution). Reds start the game.
m=>(p=[...'5555555'],g=(c,s=o='')=>/1|2/.test(m)?[1,13,15,17].some(n=>eval(`/(5|6)(.{${n}}\1){3}/`).test(m))?o:p.map((y,x)=>m[(m[y][x]|=4)^c||p[g(c^3,s+x,p[x]--),x]++,y][x]&=3)&&o:o=s)(5)
Try it online!
answered 1 hour ago
ArnauldArnauld
73.6k689309
$endgroup$
add a comment |
$begingroup$
JavaScript (ES6), 202 188 bytes
Takes input as a matrix with $1$ for red, $2$ for yellow and $0$ for empty. Returns a string of 0-indexed moves (or an empty string if there's no solution). Reds start the game.
m=>(p=[...'5555555'],g=(c,s=o='')=>/1|2/.test(m)?[1,13,15,17].some(n=>eval(`/(5|6)(.{${n}}\1){3}/`).test(m))?o:p.map((y,x)=>m[(m[y][x]|=4)^c||p[g(c^3,s+x,p[x]--),x]++,y][x]&=3)&&o:o=s)(5)
Try it online!
answered 1 hour ago
ArnauldArnauld
73.6k689309
$endgroup$
add a comment |
$begingroup$
JavaScript (ES6), 202 188 bytes
Takes input as a matrix with $1$ for red, $2$ for yellow and $0$ for empty. Returns a string of 0-indexed moves (or an empty string if there's no solution). Reds start the game.
m=>(p=[...'5555555'],g=(c,s=o='')=>/1|2/.test(m)?[1,13,15,17].some(n=>eval(`/(5|6)(.{${n}}\1){3}/`).test(m))?o:p.map((y,x)=>m[(m[y][x]|=4)^c||p[g(c^3,s+x,p[x]--),x]++,y][x]&=3)&&o:o=s)(5)
Try it online!
answered 1 hour ago
ArnauldArnauld
73.6k689309
$endgroup$
JavaScript (ES6), 202 188 bytes
Takes input as a matrix with $1$ for red, $2$ for yellow and $0$ for empty. Returns a string of 0-indexed moves (or an empty string if there's no solution). Reds start the game.
m=>(p=[...'5555555'],g=(c,s=o='')=>/1|2/.test(m)?[1,13,15,17].some(n=>eval(`/(5|6)(.{${n}}\1){3}/`).test(m))?o:p.map((y,x)=>m[(m[y][x]|=4)^c||p[g(c^3,s+x,p[x]--),x]++,y][x]&=3)&&o:o=s)(5)
Try it online!
answered 1 hour ago
ArnauldArnauld
73.6k689309
edited 9 mins ago
answered 1 hour ago
ArnauldArnauld
73.6k689309
answered 1 hour ago
ArnauldArnauld
73.6k689309
answered 1 hour ago
ArnauldArnauld
73.6k689309
73.6k689309
add a comment |
add a comment |
If this is an answer to a challenge…
…Be sure to follow the challenge specification. However, please refrain from exploiting obvious loopholes. Answers abusing any of the standard loopholes are considered invalid. If you think a specification is unclear or underspecified, comment on the question instead.
…Try to optimize your score. For instance, answers to code-golf challenges should attempt to be as short as possible. You can always include a readable version of the code in addition to the competitive one.
Explanations of your answer make it more interesting to read and are very much encouraged.…Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.
More generally…
…Please make sure to answer the question and provide sufficient detail.
…Avoid asking for help, clarification or responding to other answers (use comments instead).
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$begingroup$
Could you, eg, take the board as arrays of characters representing the rows, or do you have to parse the ascii with the
|, etc?$endgroup$
– Jonah
4 hours ago
$begingroup$
@Jpnah You can read the board in using any sensible format, including as arrays.
$endgroup$
– John Gowers
4 hours ago