题解 | #矩阵乘法#

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNextInt()) { 
            int a = in.nextInt();       //这种没法从原理优化算法的题尽量写工整点可读性强
            int b = in.nextInt();
            int c = in.nextInt();
            int[][] arr1 = new int[a][b];
            int[][] arr2 = new int[b][c];
            int[][] ans = new int[a][c];
            for (int i = 0; i < a; i++) {   //输入矩阵1
                for (int j = 0; j < b; j++) {
                    arr1[i][j]=in.nextInt();
                }
            }
            for (int i = 0; i < b; i++) {   //输入矩阵2
                for (int j = 0; j < c; j++) {
                    arr2[i][j]=in.nextInt();
                }
            }                                       //高等数学 离散数学 都学过吧
            for (int i = 0; i < a; i++) {           //最外层大循环遍历矩阵1行数
                for (int j = 0; j < c; j++) {       //中间层循环遍历矩阵2列数
                    for (int h = 0; h < b; h++) {   //最里层循环遍历矩阵1列数和矩阵2行数
                        ans[i][j] += arr1[i][h] * arr2[h][j];//求元素积之和输入到新矩阵里
                    }
                }
            }
            for (int i = 0; i < a; i++) {   //输出答案
                for (int j = 0; j < c; j++) {
                    System.out.print(ans[i][j] + " ");
                }
                System.out.println();
            }
        }
    }
}