dummy-path-finding.c

#include <stdio.h>

const int N = 5;

int solve(int map[N][N], int x, int y, int ret[N][N]) {
    if (map[y][x] == 2) {
		return 1;
    } else {
		if (y - 1 >= 0 && map[y - 1][x] != 0 && ret[y - 1][x] == 0) {
	    	ret[y - 1][x] = 1;
	    	if (solve(map, x, y - 1, ret)) {
				return 1;
	    	} else {
				ret[y - 1][x] = 0;
	    	}
		}
		if (x + 1 < N && map[y][x + 1] != 0 && ret[y][x + 1] == 0) {
	    	ret[y][x + 1] = 1;
	    	if (solve(map, x + 1, y, ret)) {
				return 1;
	    	} else {
				ret[y][x + 1] = 0;
	    	}
		}
		if (y + 1 < N && map[y + 1][x] != 0 && ret[y + 1][x] == 0) {
	    	ret[y + 1][x] = 1;
	    	if (solve(map, x, y + 1, ret)) {
				return 1;
	    	} else {
				ret[y + 1][x] = 0;
	    	}
		}
		if (x - 1 >= 0 && map[y][x - 1] != 0 && ret[y][x - 1] == 0) {
	    	ret[y][x - 1] = 1;
	    	if (solve(map, x - 1, y, ret)) {
				return 1;
	    	} else {
				ret[y][x - 1] = 0;
	    	}
		}
		return 0;
    }
}

int main() {
    int map[N][N] = {
		{1, 0, 0, 0, 2},
		{1, 1, 1, 0, 1},
		{1, 1, 1, 1, 1},
		{0, 0, 1, 0, 1},
		{0, 0, 1, 1, 1},
    };

    int ret[N][N] = {
		{1, 0, 0, 0, 0},
		{0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0},
		{0, 0, 0, 0, 0},
    };

    solve(map, 0, 0, ret);

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