Leetcode: Rotate Image @Python

class Solution:
    # @param matrix, a list of lists of integers
    # @return a list of lists of integers

    def rotate(self, matrix):
        n=len(matrix)
        sub1=n//2
        sub2=n//2 if n%2==0 else n//2+1
        for i in range(sub1):
            for j in range(sub2):
                matrix[i][j], matrix[j][n-i-1], matrix[n-i-1][n-j-1], matrix[n-j-1][i] = \
                matrix[n-j-1][i], matrix[i][j], matrix[j][n-i-1], matrix[n-i-1][n-j-1]
        return matrix