二维前缀和

#include <iostream>
using namespace std;
int n,m,q;
const int N = 1010;
int sum[N][N];
int main(){
    cin >> n >> m >> q;
    for(int i = 1;i <= n;i++){
        for(int j = 1;j <= m;j++){
        	int t;
        	cin >> t;
        	sum[i][j] = t + sum[i][j-1]+sum[i-1][j] - sum[i-1][j-1];
		}
    }
    while(q--){
    	int x1,y1,x2,y2;
    	cin >> x1 >> y1 >> x2 >> y2;
    	printf("%d\n",sum[x2][y2] - sum[x2][y1-1]-sum[x1-1][y2]+sum[x1-1][y1-1]);
	}
}