Solution (leetcode-in-java 1.20 API)

java.lang.Object
- g0601_0700.s0669_trim_a_binary_search_tree.Solution

```
public class Solution
extends Object
```
669 - Trim a Binary Search Tree.
Medium

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.

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]

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

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  TreeNode trimBST(TreeNode root, int l, int r)
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Solution
```
public Solution()
```

Method Detail

trimBST

public TreeNode trimBST(TreeNode root,
                        int l,
                        int r)