Description:
Invert a binary tree.
4
/
2 7
/ /
1 3 6 9
to
4
/
7 2
/ /
9 6 3 1
递归invert就好了。
/** * 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; invert(root); return root; } public static void invert(TreeNode root) { if(root==null || (root.right == null && root.left==null)) { return; } TreeNode rNode = root.right; TreeNode lNode = root.left; root.right = lNode; root.left = rNode; invert(root.left); invert(root.right); } }