Leetcode题解 226. Invert Binary Tree

Invert a binary tree.

     4   /   \  2     7 / \   / \1   3 6   9

to

     4   /   \  7     2 / \   / \9   6 3   1

用递归实现

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.

/** * 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(null==root){            return root;        }        invertTree(root.left);        invertTree(root.right);        TreeNode temp=root.left;        root.left=root.right;        root.right=temp;        return root;    }}