Invert a binary tree.
4 / 2 7 / \ / 1 3 6 9
to
4 / 7 2 / \ / 9 6 3 1
Trivia:
This problem was inspired by this original tweet by Max Howell:
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.
哈哈,这题是homebrew作者面Google的题目,反转二叉树。
/** * 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){ return null; } TreeNode tmp = root.left; root.left=root.right; root.right=tmp; invertTree(root.left); invertTree(root.right); return root; } }
时间: 2024-10-03 22:32:21