867. Transpose Matrix

Problem

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

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

Explain:

nope.

Complexity:

• Time complexity : O(m * n).
• Space complexity : O(m * n).