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题目:
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.
链接: http://leetcode.com/problems/invert-binary-tree/
题解:
其实我还加这哥们LinkedIn了...后来他被Apple录取了,挺好的。 使用Recursive比较快就能写出来。
Time Complexity - O(n), Space Complexity - O(n)。
/** * 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 root; TreeNode left = root.left; root.left = invertTree(root.right); root.right = invertTree(left); return root; } }
Reference:
https://leetcode.com/discuss/40001/straightforward-dfs-recursive-iterative-bfs-solutions
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原文地址:http://www.cnblogs.com/yrbbest/p/4994276.html