The following program is a sudoku solver. It can be compiled in C++ and executed with sudoku.exe <puzzle_string>, where the puzzle_string is a string of 81 characters containing the puzzle (e.g. 530070000600195000098000060800060003400803001700020006060000280000419005000080079).
#include <iostream>
#define F return false
#define T return true
#define Z bool d[10] = { false }
#define X for(int i=
using namespace std;int G[81];int S[9][9]={ {0,1,2,9,
10,11,18,19,20},{3,4,5,12, 13,14,21,22,23},{6,7,8, 15,16,17,24,25
,26},{27,28,29,36,37,38,45, 46,47},{30,31,32,39,40,41, 48,49,50},{33,34,
35,42,43 ,44,51,52,53}, {54,55,56,63,64,65,72,73,74 },{57,58,59,66,67,
68,75,76 ,77},{60, 61,62 ,69,70, 71,78,79 ,80}}; void pg()
{X 0;i< 81;i++) {if(!(i %9)&&i !=0)cout<<endl; cout<<G
[i]<<" "; }cout<< endl;} bool vr( int r){Z;X 9*r ;i<9*r+
9;i++)if(!d[G [i]]||! G[i])d[ G[i]]= true;else F;T;} bool vc
(int c){Z;X c ;i<81;i +=9)if( !d[G[i] ]||!G[i])d[G[i ]]=true
;else F;T;} bool vs (int s) {Z;X 0; i<9;i++){int j =S[s][i
];if(!d [G[j]]|| !G[j]) d[G[j]] =true;else F;} T;}bool
ps(){X 0;i<9;i ++)if(! vr(i)||! vc(i)|| !vs(i))F ;T;}void
s(int k=0){if (k>=81)return pg(); if(G[k]==0){X 1;i<= 9;i++){G[k]=i;if(ps
())s(k+1);G[k]=0;}} else s(k+1);}int main(int n,char*b[ ]){X 0;i<81;i++)G
[i]=b[1][i]-48;s()
;}The program gives the following output:
5 3 4 6 7 8 9 1 2
6 7 2 1 9 5 3 4 8
1 9 8 3 4 2 5 6 7
8 5 9 7 6 1 4 2 3
4 2 6 8 5 3 7 9 1
7 1 3 9 2 4 8 5 6
9 6 1 5 3 7 2 8 4
2 8 7 4 1 9 6 3 5
3 4 5 2 8 6 1 7 9