867-transpose-matrix

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Description

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 <= 105
• -109 <= matrix[i][j] <= 109

Solution(Python)

class Solution:
    def transpose(self, matrix: List[List[int]]) -> List[List[int]]:
        return self.zipit(matrix)

    def naive(self, matrix: List[List[int]]) -> List[List[int]]:
        m, n = len(matrix), len(matrix[0])
        res = [[0 for i in range(m)] for i in range(n)]
        for i in range(m):
            for j in range(n):
                res[j][i] = matrix[i][j]
        return res

    def oneline(self, matrix: List[List[int]]) -> List[List[int]]:
        return [
            [matrix[i][j] for i in range(len(matrix))] for j in range(len(matrix[0]))
        ]

    def zipit(self, matrix: List[List[int]]) -> List[List[int]]:
        return zip(*matrix)