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Invert a binary tree.
4 / 2 7 / \ / 1 3 6 9
to
4 / 7 2 / \ / 9 6 3 1
思路:递归。用invert左子树,存在一个node,invert右子树,存在另一个node。然后左右互换即可。今天学校食堂居然没来熊猫快递,啃了个破汉堡= =。
/** * 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 l1=invertTree(root.left); TreeNode l2=invertTree(root.right); root.right=l1; root.left=l2; return root; } }
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原文地址:http://www.cnblogs.com/Machelsky/p/5860901.html