#2583

Kth Largest Sum in a Binary Tree

specialist · 730 · lc medium +31 · verified · 59% accepted · 1,074 likes · top 56%

Description

Given the root of a binary tree and a positive integer k, compute the sum of node values at each level (depth). Return the k-th largest level sum, or -1 if the tree has fewer than k levels.

Example 1:

Input: root = [5,8,9,2,1,3,7,4,6], k = 2

Output: 13

Explanation: The level sums are the following:

- Level 1: 5.

- Level 2: 8 + 9 = 17.

- Level 3: 2 + 1 + 3 + 7 = 13.

- Level 4: 4 + 6 = 10.

The 2nd largest level sum is 13.

Example 2:

Input: root = [1,2,null,3], k = 1

Output: 3

Explanation: The largest level sum is 3.

Code

# 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:
    def kthLargestLevelSum(self, root: Optional[TreeNode], k: int) -> int:

# 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:
    def kthLargestLevelSum(self, root: Optional[TreeNode], k: int) -> int: