README_EN.md

867. Transpose Matrix

中文文档

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

Solutions

Python3

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

Java

class Solution {
    public int[][] transpose(int[][] matrix) {
        int m = matrix.length, n = matrix[0].length;
        int[][] res = new int[n][m];
        for (int i = 0; i < n; ++i) {
            for (int j = 0; j < m; ++j) {
                res[i][j] = matrix[j][i];
            }
        }
        return res;
    }
}

JavaScript

/**
 * @param {number[][]} matrix
 * @return {number[][]}
 */
var transpose = function (matrix) {
    const m = matrix.length,
        n = matrix[0].length;
    let res = [];
    for (let i = 0; i < n; ++i) {
        res[i] = [];
        for (let j = 0; j < m; ++j) {
            res[i][j] = matrix[j][i];
        }
    }
    return res;
};

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