JavaScript数组操作之旋转二维数组

/**
* @param {number[][]} matrix
* @return {void} Do not return anything, modify matrix in-place instead.
*/
var rotate = function (matrix) {
let n = matrix.length;
let res = new Array(n).fill(0).map(() => new Array(n).fill(0));
for (let i = 0; i < n; i++)
for (let j = n - 1; j >= 0; j--) res[i][n - j - 1] = matrix[j][i];
return res;
};

/**
* @param {number[][]} matrix
* @return {void} Do not return anything, modify matrix in-place instead.
*/
var rotate = function (matrix) {
let n = matrix.length;
// 先沿对角线镜像对称二维矩阵
for (let i = 0; i < n; i++) {
for (let j = i; j < n; j++) {
[matrix[i][j], matrix[j][i]] = [matrix[j][i], matrix[i][j]];
}
}
const reverseRow = (arr) => {
let i = 0,
j = arr.length - 1;
while (i <= j) {
[arr[i], arr[j]] = [arr[j], arr[i]];
i++;
j--;
}
};
// 然后反转二维矩阵的每一行
for (let row of matrix) {
reverseRow(row);
}
return matrix;
};