867. Transpose Matrix-转置矩阵

Given a 2D integer array matrix, return the transpose of matrix.

The transpose of a matrix is the matrix flipped over its main diagonal, switching the matrix’s row and column indices.

Example 1:
Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]

Example 2:
Input: matrix = [[1,2,3],[4,5,6]]
Output: [[1,4],[2,5],[3,6]]

Constraints:

• m == matrix.length
• n == matrix[i].length
• 1 <= m, n <= 1000
• 1 <= m * n <= 10^5
• -10^9 <= matrix[i][j] <= 10^9

Solution in python:

class Solution:
    def transpose(self, matrix: List[List[int]]) -> List[List[int]]:
        r = len(matrix)
        c = len(matrix[0])
        new_matrix = [[None for i in range(r)] for j in range(c)]
        for i in range(r):
            for j in range(c):
                new_matrix[j][i] = matrix[i][j]
        return new_matrix