题目描述

翻转一颗二叉树

测试用例

代码实现

/**
 * Definition for a binary tree node.
 * function TreeNode(val) {
 *     this.val = val;
 *     this.left = this.right = null;
 * }
 */
/**
 * @param {TreeNode} root
 * @return {TreeNode}
 */
var mirrorTree = function(root) {
    // 先序遍历
    if(root == null){
        return root;
    }
    // 交换
    [root.left, root.right] = [root.right, root.left];
    mirrorTree(root.left);
    mirrorTree(root.right);
    return root;
};