first step: #include <stdio.h> #include <time.h> #include <stdlib.h> int main() { int i,j; char a[9][9]={ {'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'}}; for(i=0;i<9;i++) { for(j=0;j<9;j++) { printf("%c",a[i][j]); } printf("\n") ; } return 0; }

second step: #include <stdio.h> #include <time.h> #include <stdlib.h> int main() { srand(time(NULL)); int a[9][9]={0}; int b[3][3]={0}; int c[9]={0}; int d[9]={0}; int e[9]={0}; int i=0; for(i=0;i<9;i++) { c[i]=i+1; } for(i=0;i<9;i++) { int j=rand()%9; int temp=c[i]; c[i]=c[j]; c[j]=temp; } for(i=0;i<9;i++) { d[i]=i+1; } for(i=0;i<9;i++) { int j=rand()%9; int temp=d[i]; d[i]=d[j]; d[j]=temp; } for(i=0;i<9;i++) { e[i]=i+1; } for(i=0;i<9;i++) { int j=rand()%9; int temp=d[i]; e[i]=e[j]; e[j]=temp; }/<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>/ /for(i=0;i<9;i++) { printf("%d",c[i]); } printf("\n"); for(i=0;i<9;i++) { printf("%d",d[i]); } printf("\n"); for(i=0;i<9;i++) { printf("%d",e[i]); }<7D><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>/ int p=0; for(i=0;i<3;i++) { int j; for(j=0;j<3;j++) { a[i][c[p]-1]=d[p]; p++; }

}
p=0;
for(i=3;i<6;i++)
{
	int j;
	for(j=0;j<3;j++)
	{
		a[i][d[p]-1]=e[p];
		p++;
	}

}
p=0;
for(i=6;i<9;i++)
{
	int j;
	for(j=0;j<3;j++)
	{
		a[i][e[p]-1]=c[p];
		p++;
	}

}
for(i=0;i<9;i++)
{
	int j;
	for(j=0;j<9;j++)
	{
		printf("%d",a[i][j]);
	}
	printf("\n");
}
return 0;

} third step: #include <stdio.h> #include <stdlib.h> #include <time.h> void shudu(int a[9][9]) { int flag = 0; int z = 0; int i, j, k, l; int count[10] = {0}; int m[9]; for (i = 0; i < 9; i++) { int count[10] = {0}; for (j = 0; j < 9; j++) { if (a[i][j] != 0) count[a[i][j]]++; } for (j = 0; j < 9; j++) { if (count[j + 1] >= 2) { flag = 1; z = j + 1; break; } } if (flag == 1) break; } if (flag == 1) { printf("False:Invalid initialSudoku matrix\nThe number %d in the row %d has been used!,z,j"); return ; } for (i = 0; i < 9; i++) { int count[10] = {0}; for (j = 0; j < 9; j++) { if (a[j][i] != 0) count[a[j][i]]++; } for (j = 0; j < 9; j++) { if (count[j + 1] >= 2) { flag = 1; z = j + 1; break; } } if (flag == 1) break; } if (flag == 1) { printf("FalseInvalid initial Sudoku matrix\nThe number %d in the col %d has been used!", z, j); return ; } for (i = 0; i < 3; i++) { for (j = 0; j < 3; j++) { for (k = 0; k < 3; k++) { for (l = 0; l < 3; l++) { m[k * 3 + l] = a[j * 3 + k][i * 3 + l]; } } for (k = 0; k < 9; k++) count[k] = 0; for (k = 0; k < 9; k++) { if (m[k] != 0) count[m[k]]++; } for (k = 0; k < 9; k++) { if (count[k] >= 2) { flag = 1; z = k; break; } } if (flag == 1) break; } if (flag == 1) break; } if (flag == 1) { printf("False:Invalid initial Sudoku matrix!\nThe number %d in the block %d has been used!", z, j); return ; } else printf("Ture:Valid initial sudoku matrix"); }

int main() { int i,j; int board0[9][9] = {{5, 3, 0, 0, 7, 0, 0, 0, 0}, {6, 0, 0, 1, 9, 5, 0, 0, 0}, {0, 9, 8, 0, 0, 0, 0, 6, 0}, {8, 0, 0, 0, 6, 0, 0, 0, 3}, {4, 0, 0, 8, 0, 3, 0, 0, 1}, {7, 0, 0, 0, 2, 0, 0, 0, 6}, {0, 6, 0, 0, 0, 0, 2, 8, 0}, {0, 0, 0, 4, 1, 9, 0, 0, 5}, {0, 0, 0, 0, 8, 0, 0, 7, 9} }; printf("The original Sudoku matrix:\n"); for (i = 0; i < 9; i++) { for (j = 0; j < 9; j++) { printf("%d ", board0[i][j]); } printf("\n"); } printf("\n"); shudu(board0);

} fourth step:

#include <stdio.h> #include <stdlib.h> #define N 3 #define M 9 #include<stdio.h> int x[M][M]={{5, 3, 0, 0, 7, 0, 0, 0, 0}, {6, 0, 0, 1, 9, 5, 0, 0, 0}, {0, 9, 8, 0, 0, 0, 0, 6, 0}, {8, 0, 0, 0, 6, 0, 0, 0, 3}, {4, 0, 0, 8, 0, 3, 0, 0, 1}, {7, 0, 0, 0, 2, 0, 0, 0, 6}, {0, 6, 0, 0, 0, 0, 2, 8, 0}, {0, 0, 0, 4, 1, 9, 0, 0, 5}, {0, 0, 0, 0, 8, 0, 0, 7, 9}}; void Solve(int r, int c);
int checkedbox(int r); int checked(int r, int c, int num); int* getData(int r, int c,int data); void show(void); void Solve(int r, int c) { int i; if (r == M) { show(); return; } if (c == 0 && (r == N || r == N2)) { if (checkedbox(r) == 0) { return; } } if (c == M) { Solve(r+1, 0); return; } if (x[r][c] == 0) { for (i = 1; i <= M; i++) { if (checked(r,c,i) == 1) { x[r][c]=i; Solve(r, c+1); x[r][c]=0; } } } else{ Solve(r, c+1); } } int checkedbox(int r) { int i,j,c; int *data = malloc(sizeof(int)M); for (c = 0; c < M; c+=N) { data = getData(r,c,data); for(i = 0; i < M-1 ; i++) { for(j = i+1 ; j < M ; j++) { if(data[i] == data[j]) { return 0; } } } } free(data); return 1;
} int getData(int r, int c,int *data){ int i,j,k = 0; for (i = r-N; i < r ; i++) { for(j = c; j < c+N ; j++){ data[k++] = x[i][j]; } } return data; } int checked(int r, int c, int num) { int j = 0,flag = 1; for (j = 0; j < M; j++) { if (x[j][c]==num || x[r][j]==num) { flag = 0; } } return flag; } void show(void) { int i,j; for (i = 0; i < M; i++) { for (j = 0; j < M; j++) { printf("%d ",x[i][j]); } printf("\n"); } printf("\n"); } int main(void) { int a[9][9]={{5, 3, 0, 0, 7, 0, 0, 0, 0}, {6, 0, 0, 1, 9, 5, 0, 0, 0}, {0, 9, 8, 0, 0, 0, 0, 6, 0}, {8, 0, 0, 0, 6, 0, 0, 0, 3}, {4, 0, 0, 8, 0, 3, 0, 0, 1}, {7, 0, 0, 0, 2, 0, 0, 0, 6}, {0, 6, 0, 0, 0, 0, 2, 8, 0}, {0, 0, 0, 4, 1, 9, 0, 0, 5}, {0, 0, 0, 0, 8, 0, 0, 7, 9}}; int i,j; printf("The original Sudoku matrix: \n"); for(i=0;i<9;i++) { for(j=0;j<9;j++) { printf("%d ",a[i][j]); } printf("\n"); } int det=0;/0=<3D>ԡ<EFBFBD>1=<3D><><EFBFBD><EFBFBD>/ for(i=0;i<9;i++) { int d1[9]={1,2,3,4,5,6,7,8,9}; int d2[9]={0}; for(j=0;j<9;j++) { int t=1; for(t=1;t<=9;t++) { if(a[i][j]==t) d2[t-1]++; } for(t=0;t<9;t++) { if(d2[t]>=2) { det=1; printf("False:Invalid initial Sudoku matrix!\n"); printf("The number %d in the row %d has been used!\n",t+1,i+1); printf("No solution!"); break; } } if(det==1) break; } } if(det==0) { for(i=0;i<9;i++) { int d1[9]={1,2,3,4,5,6,7,8,9}; int d2[9]={0}; for(j=0;j<9;j++) { int t=1; for(t=1;t<=9;t++) { if(a[j][i]==t) d2[t-1]++; } for(t=0;t<9;t++) { if(d2[t]>=2) { det=1; printf("False:Invalid initial Sudoku matrix!\n"); printf("The number %d in the col %d has been used!\n",t+1,i+1); break; } } if(det==1) break; } } } if(det==0) { int number = 0; int row=0 ; for(i=0;i<9;i=i+3) { for(row=0;row<9;row=row+3) { int d1[9]={1,2,3,4,5,6,7,8,9}; int d2[9]={0}; for(j=i;j<i+3;j++) { number++; int q; for(q=row;q<row+3;q++) { int t=1; for(t=1;t<=9;t++) { if(a[j][q]==t) d2[t-1]++; } for(t=0;t<9;t++) { if(d2[t]>=2) { det=1; printf("False:Invalid initial Sudoku matrix!\n"); printf("The number %d in the block %d has been used!\n",t+1,number); break; } } if(det==1) break; } } } } } if(det==0) {printf("True:Valid initial Sudoku matrix!\n"); printf("The solution of Sudoku matrix:\n");} Solve(0,0); return 0; }