867. 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

Soln:

In JS:

var transpose = function(matrix) {

    const result = [];

    for (let i = 0; i < matrix.length; i++) {

        for (let j = 0; j < matrix[0].length; j++) {

            if (!result[j]) result[j] = [];

            result[j].push(matrix[i][j])

        }

    }

    return result;

};