题目

https://www.nowcoder.com/practice/bf358c3ac73e491585943bac94e309b0?tpId=190&&tqId=36251&rp=1&ru=/activity/oj&qru=/ta/job-code-high-rd/question-ranking

import java.util.*;


public class Solution {
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     * 
     * @param a int整型二维数组 第一个矩阵
     * @param b int整型二维数组 第二个矩阵
     * @return int整型二维数组
     */
    public static int[][] solve (int[][] a, int[][] b) {
        if (a.length == 0 ){
            return a;
        }
        int[][] result = new int[a.length][a[0].length];
        for (int i = 0; i < a.length; i++) {
            for (int j = 0; j < a[i].length; j++) {
                int sum = 0;
                for (int k = 0; k < a.length; k++) {
                    sum += a[i][k] * b[k][j];
                }
                result[i][j] = sum;
            }
        }
        return result;
        // write code here
    }
}