Recover Binary Search Tree

 1 /**
 2  * Definition for binary tree
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 import java.util.ArrayList;
11 import java.util.Arrays;
12 import java.util.List;
13 
14 public class Solution {
15     List<TreeNode> listOfInOrder = new ArrayList<TreeNode>();
16     
17     public void recoverTree(TreeNode root) {
18         inOrderTravel(root);
19         int nums[] = new int[listOfInOrder.size()];
20         for(int i = 0; i < nums.length; i++){
21             nums[i] = listOfInOrder.get(i).val;
22         }//for
23         
24         Arrays.sort(nums);                             //对数组升序排列
25         for(int i = 0; i < nums.length; i++)
26             listOfInOrder.get(i).val = nums[i];
27     }
28     
29     /**
30      * 中序遍历，节点放到list中
31      * @param root
32      */
33     private void inOrderTravel(TreeNode root){
34         if(root != null){
35             inOrderTravel(root.left);
36             listOfInOrder.add(root);
37             inOrderTravel(root.right);
38         }
39     }
40 }