QWQ怎么回事 思路觉得妹错啊 为啥子代码爆了

#include <iostream>
#include <algorithm>
using namespace std;
const int N = 110;
int n, m;
int fx[4] = { -1,0,0,1 };
int fy[4] = { 0,1,-1,0 };
int g[N][N];
void dfs(int x, int y) {
    int r, c;
    g[x][y] = 0;
    for (int i = 0;i < 4;i++) {
        r = x + fx[i];
        c = y + fy[i];
        if (r <= 0 || r > n || c <= 0 || c > m||g[r][c]==0)
            continue;
        g[r][c] = 0;
        dfs(r, c);
    }
}
int ans;
int main() {
    cin >> n >> m;
    for (int i = 1;i <= n;i++) {
        for (int j = 1;j <= m;j++) {
            cin >> g[i][j];
        }
    }
    for (int i = 1;i <= n;i++) {
        for (int j = 1;j <= m;j++) {
            if (g[i][j] != 0) {
                ans++;
                dfs(i, j);
            }
        }
    }
    cout << ans;
}