Algorithms—226.Summary Ranges

思路：左右互换，递归做。

/** * Definition for a binary tree node. * public class TreeNode { *     int val; *     TreeNode left; *     TreeNode right; *     TreeNode(int x) { val = x; } * } */public class Solution {    public TreeNode invertTree(TreeNode root) {if (root != null) {TreeNode node = root.left;root.left = root.right;root.right = node;root.left = invertTree(root.left);root.right = invertTree(root.right);}        return root;    }}

耗时：308ms，中下游。leetcode也会卖萌：

Google: 90% of our engineers use the software you wrote (Homebrew), but you can’t invert a binary tree on a whiteboard so fuck off.