每日训练 -旋转图像

 1 /**
 2  * @param {number[][]} matrix
 3  * @return {void} Do not return anything, modify matrix in-place instead.
 4  */
 5 var rotate = function(matrix) {
 6     let i = 0,
 7       j = matrix.length - 1,
 8       rowIndex = 0,
 9       colIndex = matrix.length - 1,
10       exchange = 0;
11     while (i < matrix.length - 1 && j >= 0) {
12       exchange = matrix[i][rowIndex];
13       matrix[i][rowIndex] = matrix[j][colIndex];
14       matrix[j][colIndex] = exchange;
15       rowIndex++;
16       j--;
17 
18       if (rowIndex == colIndex) {
19         i++;
20         rowIndex = 0;
21         j = matrix.length - 1;
22         colIndex--;
23       }
24     }
25     matrix.reverse()
26 };