Given the root of a binary search tree and the lowest and highest boundaries as low and high, trim the tree so that all its elements lies in [low, high]. Trimming the tree should not change the relative structure of the elements that will remain in the tree (i.e., any node's descendant should remain a descendant). It can be proven that there is a unique answer.

Return the root of the trimmed binary search tree. Note that the root may change depending on the given bounds.

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Example 1:

Input: root = [1,0,2], low = 1, high = 2
Output: [1,null,2]


Example 2:

Input: root = [3,0,4,null,2,null,null,1], low = 1, high = 3
Output: [3,2,null,1]


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Constraints:


	The number of nodes in the tree is in the range [1, 104].
	0 &lt;= Node.val &lt;= 104
	The value of each node in the tree is unique.
	root is guaranteed to be a valid binary search tree.
	0 &lt;= low &lt;= high &lt;= 104


class Solution:
	def trimBST(self, root: TreeNode, low: int, high: int) -> TreeNode:
		if not root: return root
		if root.val < low: return self.trimBST(root.right, low, high)
		if root.val > high: return self.trimBST(root.left, low, high)
		root.left = self.trimBST(root.left, low, high)
		root.right = self.trimBST(root.right, low, high)
		return root
class Solution {
    public TreeNode trimBST(TreeNode root, int low, int high) {
        if (root == null) return root;
        while (root.val < low || root.val > high) {
            root = root.val < low ? root.right : root.left;
            if (root == null)
                return root;
        }
        root.left = trimBST(root.left, low, high);
        root.right = trimBST(root.right, low, high);
        return root;
    }
}
class Solution {
public:
    TreeNode* trimBST(TreeNode* root, int low, int high) {
        if(!root) return NULL;
        
        root->left = trimBST(root->left, low, high);
        root->right = trimBST(root->right, low, high);
        
        if(root->val < low){
            if(root->right){
                TreeNode* temp = root;
                // delete root;
                return temp->right;
            }else{
                return NULL;
            }
        }
        if(root->val > high){
            if(root->left){
                TreeNode* temp = root;
                // delete root;
                return temp->left;
            }else{
                return NULL;
            }
        }
        return root;
    }
};
var trimBST = function(root, low, high) {
    if(!root) return null;
    const { val, left, right } = root;
    if(val < low) return trimBST(root.right, low, high);
    if(val > high) return trimBST(root.left, low, high);
    
    root.left = trimBST(root.left, low, high);
    root.right = trimBST(root.right, low, high);
    return root;
};
Trim a Binary Search Tree