题解 | #【模板】静态矩阵和（二维前缀和）#

使用二维前缀和即可，需要注意不定长的二维数组可以使用vector

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1005;
int __t = 1, n, m, q, x11, y11, x2, y2;
void solve() {
    cin >> n >> m >> q;
    vector<vector<int>> a(n + 1, vector<int>(m + 1, 0)),
        sum(n + 1, vector<int>(m + 1, 0));
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
            sum[i][j] =
                a[i][j] + sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1];
        }
    while (q--) {
        cin >> x11 >> y11 >> x2 >> y2;
        int ans = sum[x2][y2] - sum[x11 - 1][y2] - sum[x2][y11 - 1] +
                  sum[x11 - 1][y11 - 1];
        cout << ans << '\n';
    }
}
int32_t main() {
#ifdef ONLINE_JUDGE
    ios::sync_with_stdio(false);
    cin.tie(0);
#endif
    // cin >> __t;
    while (__t--)
        solve();
    return 0;
}