horse in the chess

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <time.h>

#define SIDE 8

int chess[SIDE][SIDE]; // chess[i][j] = counter++

void print_chess() {
    for (int i = 0; i < SIDE; ++i) {
        for (int j = 0; j < SIDE; ++j) {
            printf("%3d", chess[i][j]);
        }
        printf("\n");
    }
    printf("\n");
}

#define MAXDIRS 8

int dirs[MAXDIRS][2] = { { +1, -2 }, { +2, -1 }, { +2, +1 }, { +1, +2 },
                         { -1, +2 }, { -2, +1 }, { -2, -1 }, { -1, -2 } };

#define MAXSTEP (SIDE * SIDE)

int path[MAXSTEP][2]; // { { x1, y1 }, { x2, y2 }, ... }

bool is_passable(int i, int j) {
    return 0 <= i && i < SIDE && 0 <= j && j < SIDE && chess[i][j] == 0;
}

int steps_at(int i, int j) {
    int steps = 0;
    for (int k = 0; k < MAXDIRS; ++k) {
        int x = i + dirs[k][0];
        int y = j + dirs[k][1];
        is_passable(x, y) && steps++;
    }
    return steps;
}

void solve(int i, int j, int counter) {
    chess[i][j] = counter;
    int nextx = -1, nexty, minsteps = MAXSTEP;
    for (int k = 0; k < MAXDIRS; ++k) {
        int x = i + dirs[k][0];
        int y = j + dirs[k][1];
        if (is_passable(x, y) && steps_at(x, y) <= minsteps) {
            minsteps = steps_at(x, y);
            nextx = x, nexty = y;
        }
    }
    if (nextx != -1) {
        solve(nextx, nexty, counter + 1);
    }
}

int main() {
    srand((unsigned int)time(NULL));
    solve(rand() % SIDE, rand() % SIDE, 1);
    print_chess();
}