// @Title: 修剪二叉搜索树 (Trim a Binary Search Tree)
// @Author: qisiii
// @Date: 2024-09-16 18:27:52
// @Runtime: 0 ms
// @Memory: 43.2 MB
// @comment: 
// @flag: 
/**
 * 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 {
    public TreeNode trimBST(TreeNode root, int low, int high) {
        if(root==null){
            return null;
        }
        if(root.val==low){
            root.left=null;
        }else if(root.val<low){
         return trimBST(root.right,low,high);
        }
        if(root.val==high){
            root.right=null;
        }else if(root.val>high){
         return trimBST(root.left,low,high);
        }
        root.left=trimBST(root.left,low,high);
        root.right=trimBST(root.right,low,high);
        return root;
    }
    
    
}