AcWing <796. 子矩阵的和>

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int N = 1010;
int a[N][N], s[N][N];
int n, m, q;
int main()
{
  scanf("%d%d%d", &n, &m, &q);
  for (int i = 1; i <= n; i++)
  {
    for (int j = 1; j <= m; j++)
    {
      scanf("%d", &a[i][j]);
    }
  }
  for (int i = 1; i <= n; i++)
  {
    for (int j = 1; j <= m; j++)  //二维前缀和的初始化
    {
      s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + a[i][j];
    }
  }
  while (q--)
  {
    int x1, y1, x2, y2;
    scanf("%d%d%d%d", &x1, &y1, &x2, &y2);  //求子矩阵的和
    printf("%d\n", s[x2][y2] - s[x2][y1 - 1] - s[x1 - 1][y2] + s[x1 - 1][y1 - 1]);
  }
  return 0;
}