题解 | #矩阵乘法#

import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int a = in.nextInt();
            int b = in.nextInt();
            int c = in.nextInt();

            int[][] arr = new int[a][b];
            int[][] brr = new int[b][c];
            
            //存第一个矩阵
            for (int i = 0; i < a; i++) {
                for (int j = 0; j < b; j++) {
                    arr[i][j] = in.nextInt();
                }
            }
            //存第二个矩阵
            for (int i = 0; i < b; i++) {
                for (int j = 0; j < c; j++) {
                    brr[i][j] = in.nextInt();
                }
            }

            //代入矩阵公式
            for (int i = 0; i < a; i++) {
                for (int k = 0; k < c; k++) {
                    int sum = 0;
                    for (int j = 0; j < b; j++) {
                        sum = sum + arr[i][j] * brr[j][k];
                    }
                    System.out.print(sum + " ");
                }
                System.out.println();
            }
        }
    }
}