Leetcode--Invert Binary Tree

Question:

Invert a binary tree.

     4   /     2     7/\   /1   3 6   9

To

     4   /     7     2/\   /9   6 3   1

Trivia:
This problem is inspired by this original tweets by Max Howell:

google:90% of our engineers with the software you wrote (Homebrew), but can ' t invert a binary tree on a Whitebo ard so fuck off.

Analysis:

Problem Description: Give a binary tree, then replace it with the left and right sub-tree.

Idea: This topic should be reflected to recursion first. There are two conditions for recursion: The writing of the return statement and the writing of the recursive statement. In this topic, as long as a node has any left node or right node, they should be replaced. So as long as the non-empty replacement

。

Answer:

/*** Definition for a binary tree node. * public class TreeNode {* int val; * TreeNode left; * TreeNode rig Ht * TreeNode (int x) {val = x;} }*/ Public classSolution { PublicTreeNode inverttree (TreeNode root) {if(Root = =NULL)              returnRoot; TreeNode T=Root.left; Root.left=Root.right; Root.right=T;      Inverttree (Root.left);      Inverttree (Root.right); returnRoot; }}

Leetcode--Invert Binary Tree