题解 | 【模板】二维前缀和

#include <bits/stdc++.h>
#include <cstdlib>

using namespace std;
const int N = 1e3 + 10;
typedef long long ll;
ll s[N][N], a[N][N];
int main() {
    int n, m, q;
    cin >> n >> m >> q;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + a[i][j];
        }
    }
    for (int i = 0; i < q; i++) {
        int x1, x2, y1, y2;
        cin >> x1 >> y1 >> x2 >> y2;
        cout << s[x2][y2] - s[x1 - 1][y2] - s[x2][y1 - 1] + s[x1 - 1][y1 - 1] << '\n';
    }
    return 0;
}