[Python] 행렬의 곱셈

https://school.programmers.co.kr/learn/courses/30/lessons/12949

프로그래머스

def solution(arr1, arr2):
    answer = []
    
    for i in range(len(arr1)):
        row = []
        
        for j in range(len(arr2[0])):
            a = 0
            for k in range(len(arr1[0])):
                a += arr1[i][k] * arr2[k][j]
            row.append(a)
            
        answer.append(row)
        
    return answer