题解 | #【模板】静态矩阵和（二维前缀和）#

#include <stdio.h>
#define ll long long

int main() {
    int n, m, q;
    if (scanf("%d %d %d", &n, &m, &q) != EOF) {
        ll matrix[n + 1][m + 1], matrixsum[n + 1][m + 1];
        for(int i = 0; i < n; i++) {
            matrixsum[0][i] = 0;
            matrixsum[i][0] = 0;
        }
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= m; j++) {
                if(scanf("%lld", &matrix[i][j]) != EOF) {
                    matrixsum[i][j] = matrixsum[i - 1][j] + matrixsum[i][j - 1] - matrixsum[i - 1][j - 1] + matrix[i][j];
                } else printf("error2\n");
            }
        }

        while(q--) {
            int x1, y1, x2, y2;
            if(scanf("%d %d %d %d", &x1, &y1, &x2, &y2) != EOF) {
                printf("%lld\n", matrixsum[x2][y2] - matrixsum[x1 -1][y2] - matrixsum[x2][y1 - 1] + matrixsum[x1 - 1][y1 - 1]);
            } else printf("error3\n");
        }
    } else printf("error1\n");
    return 0;
}