I have this task: 'Write a program that adds two square matrices. The program will read the dimension of the matrix, N, and will then read N*N numbers representing the first matrix, row by row. It will then read another N*N numbers representing the second matrix. The program will output the resulting matrix, one row per line. ' for which I wrote the code below. However, the platform I am doing the task on keeps saying that 1 of 2 tests failed...It works just fine for me. Maybe the problem is on their side?

from operator import add
#Enter a digit for you matrix, e.g if you want it to be 2x2 enter 2
n = int(input())
#Input digits for both matrixes rows one at a time
matrix1_r1 = [int(input()) for x in range(n)]
matrix1_r2 = [int(input()) for x in range(n)]

matrix2_r1 = [int(input()) for x in range(n)]
matrix2_r2 = [int(input()) for x in range(n)]

final1 = list(map(add, matrix1_r1, matrix2_r1))
final2 = list(map(add, matrix1_r2, matrix2_r2))

print(final1)
print(final2)

Their sample innput is:

2
1
2
3
4
5
6
7
8

their sample output is:

[6, 8]
[10, 12]

CodePudding user response：

Your code works for the example, and for any input that is 2 by 2. It will fail for any other sized matrix, because your code only computes two rows for each matrix. Rather than hard-coding something so fundamental, you should be using nested loops and a list of lists to get the right number of rows. Or, if you want to be a little fancy, list comprehensions can do it all really neatly:

n = int(input())

matrix1 = [[int(input()) for col in range(n)] for row in range(n)]
matrix2 = [[int(input()) for col in range(n)] for row in range(n)]

matrix_sum = [[a   b for a, b in zip(row1, row2)] for row1, row2 in zip(matrix1, matrix2)]

print(*matrix_sum, sep='\n')