669. Trim a Binary Search Tree

https://leetcode.com/problems/trim-a-binary-search-tree/

Python

class Solution:
    def trimBST(self, root: Optional[TreeNode], low: int, high: int) -> Optional[TreeNode]:
        return self.trim(root, low, high)

    def trim(self, node, low, high):
        if not node:
            return

        if node.val > high:
            return self.trim(node.left, low, high)
        elif node.val < low:
            return self.trim(node.right, low, high)
        else:
            node.left = self.trim(node.left, low, high)
            node.right = self.trim(node.right, low, high)
            return node