Code:
/* SudokuEZ.c - a concise sudoku brute force program, Author unknown.
status: na
This program was written using Turbo C.
Users of newer compilers should:
1) include the windows.h file line, if you don't have conio.h
2) include the define gotoxy file line
3) change CLK_TCK to TICKS_PER_SEC
All users should know that this program has not been tested,
beyond a a very low level. We're just experimenting with it,
at this time.
*/
//#include <windows.h> //for older compilers, don't include this line
//#define gotoxy Gotoxy // " " " " " " "
#include <stdio.h>
#include <conio.h>
#include <time.h>
int grid[9][9];
int benchmark(FILE *);
void Gotoxy(int x, int y);
void load(void);
void printIt(void);
void print_solution(void);
int safe(int row, int col, int n);
void solve(int row, int col, int format);
/* format == 0, show solutions, format == 1, don't show solutions */
int benchmark(FILE* fp) {
clock_t start, stop;
int c, r, temp;
unsigned long puzzNum = 0;
if((fp = fopen("Top150.txt", "rt")) == NULL) {
perror("\n Error opening Top150.txt file - terminating program ");
return 1;
}
start = clock();
temp = 0;
while(temp != EOF) {
for(r = 0; r < 9; r++) {
for(c = 0; c < 9; c++) {
temp = fgetc(fp);
if(temp == '.') temp = 0;
else
temp = temp - '0';
grid[r][c] = temp;
}
}
temp = fgetc(fp); //pulls off the newline
if(temp == EOF) continue;
printIt();
gotoxy(1,16);
printf(" Working on puzzle number: %ld", ++puzzNum);
//if(puzzNum > 100) break;
//getch(); getch();
solve(0,0,1);
}
stop = clock();
gotoxy(1, 18);
//newer compiler? replace CLK_TCK with TICKS_PER_SEC
printf(" Elapsed time was: %.2f seconds", (stop-start)/CLK_TCK);
printf("\n\n\t\t Benchmark complete - press enter when ready");
while((temp = getchar()) != '\n');
temp = getchar();
fclose(fp);
return 0;
}
/* Include this function, for newer compilers
void Gotoxy(int x, int y) {
COORD coord;
coord.X = x;
coord.Y = y;
SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE), coord);
}
*/
int main() {
FILE *fp;
int i, j;
char ch;
for(i=0; i< 10; i++)
printf("\n\n\n\n\n");
do {
for(i=3; i< 21; i++) {
gotoxy(1,i);
printf(" ");
}
gotoxy(1,3);
printf("\t\t Welcome to Sudoku Solver's Main Menu\n\n");
printf(" *press 'b' to benchmark this program\n\n");
printf(" *press 'l' to load a puzzle from this program\n\n");
printf(" *press 'e' to enter your own puzzle, or 'q' to quit [b/l/e/q]: ");
for(i=0; i < 9; i++) {
for(j = 0; j < 9; j++) {
grid[i][j] = 0;
}
}
ch=getchar();
if(ch == 'q') break;
for(i=3; i< 10; i++) {
gotoxy(1,i);
printf(" ");
}
if(ch == 'b') {
gotoxy(1,2);
printf("\t\t Sudoku is Running a Benchmark Suite of Puzzles");
j = benchmark(fp);
if(j) return 1;
}
else if(ch == 'l')
load();
else if(ch == 'e') {
printf("enter your puzzle: \n");
for(i=0;i<9;i++) {
for(j=0;j<9;j++) {
printf("(%d, %d): ", i+1, j+1);
scanf("%d", &grid[i][j]);
}
}
}
if(ch != 'b') {
printIt();
solve(0,0,0);
gotoxy(1, 22);
printf("\t\t\t Press enter when ready");
i = getchar();
gotoxy(1,22);
printf("\t\t\t ");
}
}while(ch != 'q');
gotoxy(1, 22);
printf("\t\t Program complete, press enter when ready");
while((i = getchar()) != '\n');
i = getchar();
return 0;
}
void load(void) {
int c, gar;
gotoxy(1,6);
printf(" There are four very hard puzzles. Choose 1, 2, 3 or 4: ");
scanf("%d", &c);
gar = getchar();
gotoxy(1,6);
printf(" ");
if(c == 1) {
/*sudoku17.txt Game 9 Tough!.*/
/*000000012 400090000 000000050 070200000 600000400 000108000
018000000 000030700 502000000*/
grid[0][7] = 1; grid[0][8] = 2; grid[1][0] = 4; grid[1][4] = 9; grid[2][7] = 5;
grid[3][1] = 7; grid[3][3] = 2; grid[4][0] = 6; grid[4][6] = 4; grid[5][3] = 1;
grid[5][5] = 8; grid[6][1] = 1; grid[6][2] = 8; grid[7][4] = 3; grid[7][6] = 7;
grid[8][0] = 5; grid[8][2] = 2;
} /*This game ^^ is a great testbed - Very hard. Solution starts with 367 485 912*/
else if(c == 2) {
/*VH 2: "near worst case for brute force sudoku solver" - Wikipedia
My solve time: 0.22 seconds */
grid[1][5] = 3; grid[1][7] = 8; grid[1][8] = 5;
grid[2][2] = 1; grid[2][4] = 2;
grid[3][3] = 5; grid[3][5] = 7;
grid[4][2] = 4; grid[4][6] = 1;
grid[5][1] = 9;
grid[6][0] = 5; grid[6][7] = 7; grid[6][8] = 3;
grid[7][2] = 2; grid[7][4] = 1;
grid[8][4] = 4; grid[8][8] = 9;
}
else if(c == 3) {
/*VH 3: Sudoku17.txt #11 - one of my hardest to solve, Time: 3 seconds
000000012 700060000 000000050 080200000 600000400 000109000
019000000 000030800 502000000*/
grid[0][7] = 1; grid[0][8] = 2;
grid[1][0] = 7; grid[1][4] = 6;
grid[2][7] = 5;
grid[3][1] = 8; grid[3][3] = 2;
grid[4][0] = 6; grid[4][6] = 4;
grid[5][3] = 1; grid[5][5] = 9;
grid[6][1] = 1; grid[6][2] = 9;
grid[7][4] = 3; grid[7][6] = 8;
grid[8][0] = 5; grid[8][2] = 2;
}
else if(c == 4) {
/*VH 4: Sudoku17.txt #619 -
000000071 900000060 020000000 004070000 030000400
000910000 700600008 000300200 100000000 */
grid[0][7] = 7; grid[0][8] = 1;
grid[1][0] = 9; grid[1][7] = 6;
grid[2][1] = 2;
grid[3][2] = 4; grid[3][4] = 7;
grid[4][1] = 3; grid[4][6] = 4;
grid[5][3] = 9; grid[5][4] = 1;
grid[6][0] = 7; grid[6][3] = 6; grid[6][8] = 8;
grid[7][3] = 3; grid[7][6] = 2;
grid[8][0] = 1;
}
gar++;
}
void printIt(void) {
int r, c;
gotoxy(2, 3);
for(r = 0; r < 9; r++) {
printf("\n ");
if(r % 3 == 0 && r > 1)
printf("=======================\n ");
for(c = 0; c < 9; c++) {
if(c % 3 == 0 && c > 1)
printf("|| ");
if(grid[r][c]) {
//textcolor(14);
printf("%d ", grid[r][c]); //was cprintf()
//textcolor(15);
}
else
printf("%d ", grid[r][c]); //also cprintf()
}
}
//textcolor(15);
//gar = getchar(); gar++;
}
void print_solution(void) {
static int nsol = 0;
int r, c;
printf("----- solution %d -----\n", ++nsol);
for (r = 0; r < 9; r++)
{
for (c = 0; c < 9; c++)
{
printf("%d", grid[r][c]);
if (c % 3 == 2) printf(" ");
}
printf("\n");
if (r % 3 == 2) printf("\n");
}
}
int safe(int row, int col, int n)
{
int r, c, br, bc;
if (grid[row][col] == n) return 1;
if (grid[row][col] != 0) return 0;
for (c = 0; c < 9; c++)
if (grid[row][c] == n) return 0;
for (r = 0; r < 9; r++)
if (grid[r][col] == n) return 0;
br = row / 3;
bc = col / 3;
for (r = br * 3; r < (br + 1) * 3; r++)
for (c = bc * 3; c < (bc + 1) * 3; c++)
if (grid[r][c] == n) return 0;
return 1;
}
void solve(int row, int col, int format) {
int n, t;
unsigned long solNum = 0;
if (row == 9 && !format ) {
printIt(); //static grid printout
//print_solution(); //enables the rolling screen of solutions mode
solNum++;
printf("\n\n Found %ld Solution%c", solNum, solNum > 1 ? 's': ' ');
}
else {
for (n = 1; n <= 9; n++) {
if (safe(row, col, n)) {
t = grid[row][col];
grid[row][col] = n;
if (col == 8)
solve(row + 1, 0, format);
else
solve(row, col + 1, format);
grid[row][col] = t;
}
}
}
}
Comments regarding "my solver", don't refer to this program. I'll post up the Top150.txt file (used in the benchmark function), in just a bit. 
Originally Posted by iMalc
