Leetcode - 48. Rotate Image

/**
 * @param {number[][]} matrix
 * @return {void} Do not return anything, modify matrix in-place instead.
 */
var rotate = function (matrix) {

    let l = 0, r = matrix.length-1;

    while (l < r) {

        for (let i = 0; i < r - l; i++) {

            let top = l, bottom = r;

            let saveTopLeft = matrix[top][l + i];

            //move bottomLeft to topLeft
            matrix[top][l + i] = matrix[bottom - i][l];

            //move bottomRight to bottomLeft
            matrix[bottom - i][l] = matrix[bottom][r - i];


            //move topRight to bottomLeft
            matrix[bottom][r - i] = matrix[top + i][r];


            //saved to topRight
            matrix[top + i][r] = saveTopLeft

        }
        l++;
        r--;
    }

};