题解 | #矩阵乘法#

根据矩阵公式int[x][z] = int[x][y]*int[y][z];

先定义出int[x][y 和int[y][z]矩阵。然后每每列相乘得到

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.hasNext()) { // 注意 while 处理多个 case
            int x = in.nextInt();
            int y = in.nextInt();
            int z = in.nextInt();
            int[][] A = new int[x][y];
            int[][] B = new int[y][z];
            // 矩阵1
            for (int i = 0; i < x; i++) {
                for (int k = 0; k < y; k++) {
                    A[i][k] = in.nextInt();
                }
            }
            // 矩阵2
            for (int k = 0; k < y; k++) {
                for (int j = 0; j < z; j++) {
                    B[k][j] = in.nextInt();
                }
            }
            int[][] c = new int[x][z];
            for (int i = 0; i < x; i++) {
                for (int j = 0; j < z; j++) {
                    for (int k = 0; k < y; k++) {
                        c[i][j] += A[i][k] * B[k][j];
                    }
                }
            }

            // 打印
            for (int i = 0; i < x; i++) {
                for (int j = 0; j < z; j++) {
                    System.out.print(c[i][j] + " ");
                }
                System.out.print("\n");
            }

        }
    }
}