[리트코드 leetcode] 938. Range Sum of BST

leetcode.com/problems/range-sum-of-bst/

Range Sum of BST - LeetCode

풀긴 하였지만 brute force이므로 개선의 여지가 존재한다.

가지치기 방법을 생각해봐야겠다. 

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    sum =0
    def rangeSumBST(self, root: TreeNode, low: int, high: int) -> int:
        
        
        def recur(node):
            if not node:
                return
            
            node.right = recur(node.right)
            
            
            if low <= node.val <= high:
                self.sum += node.val
                
            node.left = recur(node.left)
            
            return node
        
        recur(root)
        return self.sum