Que11|796. 子矩阵的和

题目：796. 子矩阵的和 - AcWing题库

想法/思路：

代码实现：

import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int q = sc.nextInt();
        int[][] arr = new int[n][m];
        int[][] sum = new int[n + 1][m + 1];
        
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                arr[i][j] = sc.nextInt();
            }
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= m; j++) {
                sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + arr[i - 1][j - 1];
            }
        }
        while (q-- > 0) {
            int x1 = sc.nextInt();
            int y1 = sc.nextInt();
            int x2 = sc.nextInt();
            int y2 = sc.nextInt();
            int ans = sum[x2][y2] - sum[x2][y1 - 1] - sum[x1 - 1][y2] + sum[x1 - 1][ y1 - 1];
            System.out.println(ans);
        }
    }
}