/
main.c
executable file
·116 lines (87 loc) · 1.87 KB
/
main.c
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#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#define kRows 9
#define kCols 9
#define kValues 9
#define kBoxWidth 3
int grid[kRows][kCols];
int loadPuzzle (const char *path) {
FILE *file = fopen(path, "r");
if (!file)
return 0;
for (int row = 0; row < kRows; row++) {
for (int col = 0; col < kCols; col++) {
fscanf(file, "%d", &grid[row][col]);
}
}
fclose(file);
return 1;
}
int valid (int row, int col, int val) {
for (int n = 0; n < kRows; n++) {
if (grid[n][col] == val || grid[row][n] == val)
return 0;
}
int sRow = (row / kBoxWidth) * kBoxWidth;
int sCol = (col / kBoxWidth) * kBoxWidth;
for (int r = sRow; r < sRow + kBoxWidth; r++) {
for (int c = sCol; c < sCol + kBoxWidth; c++) {
if (grid[r][c] == val)
return 0;
}
}
return 1;
}
int solve (int row, int col) {
if (row == kRows)
return 1;
if (grid[row][col] != 0) {
if (col == 8)
return solve(row + 1, 0);
return solve(row, col + 1);
}
for (int val = 1; val <= kValues; val++) {
if (valid(row, col, val)) {
grid[row][col] = val;
if (col == 8) {
if (solve(row + 1, 0))
return 1;
}
else {
if (solve(row, col + 1))
return 1;
}
}
}
grid[row][col] = 0;
return 0;
}
int main (int argc, const char * argv[]) {
if (argc != 2) {
printf("Usage: sudoku /path/to/puzzle.txt\n");
return EXIT_SUCCESS;
}
char realPath[PATH_MAX + 1];
char *res = realpath(argv[1], realPath);
if (!res) {
printf("Invalid puzzle path!\n");
return EXIT_FAILURE;
}
if (!loadPuzzle(realPath)) {
printf("Couldn't load the puzzle!\n");
return EXIT_FAILURE;
}
if (solve(0, 0)) {
printf("Solution:\n\n");
for (int row = 0; row < kRows; row++) {
for (int col = 0; col < kCols; col++) {
printf("%d ", grid[row][col]);
}
printf("\n");
}
}
else
printf("No solution!\n");
return EXIT_SUCCESS;
}