题解 | 单组_二维数组

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        int a[][] = new int[n][m];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                a[i][j] = in.nextInt();
            }
        }
        long result = 0;//注意这里要用long，不然数值溢出
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                result += a[i][j];
            }
        }
        System.out.print(result);
    }
}