938. Range Sum of BST

Easy

Given the root node of a binary search tree and two integers low and high, return the sum of values of all nodes with a value in the inclusive range [low, high].

Solution

class Solution:
    def rangeSumBST(self, root: Optional[TreeNode], low: int, high: int) -> int:
        if root is None:
            return 0

        if root.val < low:
            return self.rangeSumBST(root.right, low, high)

        if root.val > high:
            return self.rangeSumBST(root.left, low, high)

        return (
            root.val
            + self.rangeSumBST(root.left, low, high)
            + self.rangeSumBST(root.right, low, high)
        )


class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right