子矩阵的和---二维前缀和模板题

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 1000+10;
int nums[N][N],s[N][N];
int n,m,q;




int main(void){
    scanf("%d%d%d",&n,&m,&q);
    
    for(int i=1;i<=n;i++){
        for(int j = 1;j<=m;j++){
            scanf("%d",&nums[i][j]);
            s[i][j] = s[i-1][j] + s[i][j-1] - s[i-1][j-1] + nums[i][j];
        }
    }
   
    int x1,y1;
    int x2,y2;
    while(q--){
        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
        printf("%d\n",s[x2][y2] - s[x1-1][y2] - s[x2][y1-1] + s[x1-1][y1-1]);
    }
    
    
    
    return 0;
}