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RecoverBinarySearchTree.java
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RecoverBinarySearchTree.java
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/*https://leetcode.com/problems/recover-binary-search-tree/*/
/*https://practice.geeksforgeeks.org/problems/fixed-two-nodes-of-a-bst/1*/
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
TreeNode previous, first, second;
public void recoverTree(TreeNode root) {
previous = first = second = null;
inorder(root);
int temp = first.val;
first.val = second.val;
second.val = temp;
}
public void inorder(TreeNode root)
{
if (root == null) return;
inorder(root.left);
if (first == null && previous != null && previous.val > root.val)
first = previous;
if (first != null && previous.val > root.val)
second = root;
previous = root;
inorder(root.right);
}
}