题解 | #【模板】二维前缀和# 动态规划方法

#include <iostream>
#include <vector>
using namespace std;

int main() 
{
    int n, m, q;
    cin >> n >> m >> q;
    vector<vector<int>> arr(n + 1,vector<int>(m + 1)); //二维数组
    vector<vector<long long>> dp(n + 1,vector<long long>(m + 1));   //记录前缀和的矩阵数组
    //dp[i][j]代表 从arr[1][1] 到arr[i][j]的所有元素之和

    for(int i = 1; i < n + 1; ++i)
        for(int j = 1; j < m + 1; ++j)
        {
            cin >> arr[i][j];
            dp[i][j] = dp[i - 1][j] + dp[i][j - 1]
             + arr[i][j] - dp[i - 1][j - 1];
        }
   int x1,y1,x2,y2;
   while(q--)
   {
        cin >> x1 >> y1 >> x2 >> y2;
        cout << dp[x2][y2] - dp[x1 - 1][y2]
        - dp[x2][y1 - 1] + dp[x1 - 1][y1 - 1] << endl;
   }
}