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].
Example 1:
Input: root = [10,5,15,3,7,null,18], low = 7, high = 15 Output: 32 Explanation: Nodes 7, 10, and 15 are in the range [7, 15]. 7 + 10 + 15 = 32.
Example 2:
Input: root = [10,5,15,3,7,13,18,1,null,6], low = 6, high = 10 Output: 23 Explanation: Nodes 6, 7, and 10 are in the range [6, 10]. 6 + 7 + 10 = 23.
Constraints:
The number of nodes in the tree is in the range [1, 2 * 104]. 1 <= Node.val <= 105 1 <= low <= high <= 105 All Node.val are unique.
- code
class Solution:
def rangeSumBST(self, root: Optional[TreeNode], low: int, high: int) -> int:
self.res = 0
def helper(root):
if not root: return
if root.val < high:
helper(root.right)
if root.val > low:
helper(root.left)
if low <= root.val <= high:
self.res += root.val
helper(root)
return self.res
- code
class Solution(object):
def rangeSumBST(self, root, L, R):
ans = 0
stack = [root]
while stack:
node = stack.pop()
if node:
if L <= node.val <= R:
ans += node.val
if L < node.val:
stack.append(node.left)
if node.val < R:
stack.append(node.right)
return ans