Solve a Sudoku grid only using magic, recursion, and 145bytes of brute force.
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Sudoku Solver in 145bytes
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function R | |
( | |
a, // the array representing the sudoko grid | |
f, // the callback function ( with a closure on 'a' ) to display the solution | |
// placeholder arguments | |
i, // index of the last empty cell | |
j, // index to check the candidates for the cell 'i' | |
m, // candidate number for the the cell 'i' | |
g // flag whether 'm' is a already used in the same row|col|node as 'i' | |
){ | |
// phase 1: look for an empty cell | |
for | |
( | |
i=80; | |
a[i]; // keep going if the cell isn't empty | |
i--||f() // decrease the index and call 'f(a)' if we went through the whole grid | |
); | |
// phase 2: check all candidate numbers for the cell 'i' | |
for | |
( | |
m=10; | |
g=a[i]=--m; // put the candidate in the cell 'i' already and set 'g' to something truthy | |
// at the end of phase 2, the cell 'i' is reset to 0 for "higher" branches of the recursion | |
g&&R(a,f) // recurse if 'm' isn't already used in the same row|col|node as 'i' | |
) | |
// phase 3: check if the candidate number is used already | |
for(j in a) // loop through the whole grid again | |
g*= // turn 'g' falsy if | |
a[j^i==j] // we are not on the cell 'i' | |
^m // and the cell 'j' is set to 'm' | |
|| // and we are in the same row|col|node as 'i' | |
i/9^j/9&&i%9^j%9&&i/27^j/27|i%9/3^j%9/3 | |
} |
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function R(a,f,i,j,m,g){for(i=80;a[i];i--||f());for(m=10;g=a[i]=--m;g&&R(a,f))for(j in a)g*=a[j^i==j]^m||i/9^j/9&&i%9^j%9&&i/27^j/27|i%9/3^j%9/3} |
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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
Version 2, December 2004 | |
Copyright (C) 2011 Mathieu 'p01' Henri <http://www.p01.org/releases/> | |
Everyone is permitted to copy and distribute verbatim or modified | |
copies of this license document, and changing it is allowed as long | |
as the name is changed. | |
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
0. You just DO WHAT THE FUCK YOU WANT TO. |
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{ | |
"name": "sudokuSolver", | |
"description": "Brute force sudoku solver.", | |
"keywords": [ | |
"sudoku", | |
"solver", | |
"recursive", | |
"brute force" | |
] | |
} |
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<!DOCTYPE html> | |
<title>Foo</title> | |
<div>Expected value: <b>4,2,8,1,5,9,6,7,3,1,9,6,3,7,4,8,2,5,3,7,5,8,6,2,9,4,1,9,8,1,4,2,3,5,6,7,5,6,4,7,1,8,3,9,2,7,3,2,5,9,6,1,8,4,2,4,3,6,8,1,7,5,9,6,1,7,9,4,5,2,3,8,8,5,9,2,3,7,4,1,6</b></div> | |
<div>Actual value: <b id="ret"></b></div> | |
<script> | |
// write a small example that shows off the API for your example | |
// and tests it in one fell swoop. | |
var testGrid = [0,0,0,1,5,0,0,7,0,1,0,6,0,0,0,8,2,0,3,0,0,8,6,0,0,4,0,9,0,0,4,0,0,5,6,7,0,0,4,7,0,8,3,0,0,7,3,2,0,0,6,0,0,4,0,4,0,0,8,1,0,0,9,0,1,7,0,0,0,2,0,8,0,5,0,0,3,7,0,0,0]; | |
var myFunction = function R(a,f,i,j,m,g){for(i=80;a[i];i--||f());for(m=10;g=a[i]=--m;g&&R(a,f))for(j in a)g*=a[j^i==j]^m||i/9^j/9&&i%9^j%9&&i/27^j/27|i%9/3^j%9/3} | |
myFunction( testGrid, (function(a){ return function(){document.getElementById( "ret" ).textContent=a;}})(testGrid) ); | |
</script> |
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