LeetCode 867. Transpose Matrix

Description

https://leetcode.com/problems/transpose-matrix/

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

Explanation

Simply assign matrix[i][j] value to the transpose matrix[j][i] cell.

Python Solution

class Solution:
    def transpose(self, matrix: List[List[int]]) -> List[List[int]]:
        transpose_matrix = [[0 for i in range(0, len(matrix))] for j in range(0, len(matrix[0]))]
        
        for i in range(0, len(matrix)):
            for j in range(0, len(matrix[0])):
                transpose_matrix[j][i] = matrix[i][j]

        return transpose_matrix
    
  • Time Complexity: O(MN).
  • Space Complexity: O(MN).

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