71. 2차원 리스트 회전과 행렬 곱 대각합

1m = [[1, 2, 3],
2     [4, 5, 6]]
3rows, cols = len(m), len(m[0])
4r = [[0] * rows for _ in range(cols)]
5for i in range(rows):
6    for j in range(cols):
7        r[j][rows - 1 - i] = m[i][j]
8for row in r:
9    print(*row)
10diag = 0
11for i in range(cols):
12    for k in range(rows):
13        diag += r[i][k] * m[k][i]
14print(diag)