Kth Largest Sum in a Binary Tree — LeetCode 2583 Python Solution
MediumTreeBreadth-First SearchBinary TreeSorting
- Problem
- #2583
- Pattern
- Tree Traversal
- Reading time
- 4 min
- Source
- leetcode.com
The problem
You are given the root of a binary tree and a positive integer k. The level sum in the tree is the sum of the values of the nodes that are on the same level.
Example
- Input
- root = [5,8,9,2,1,3,7,4,6], k = 2
- Output
- 13
- Explanation
- The level sums are the following:
Python solution
Python
# 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:
arr = []
q = deque([root])
while q:
t = 0
for _ in range(len(q)):
root = q.popleft()
t += root.val
if root.left:
q.append(root.left)
if root.right:
q.append(root.right)
arr.append(t)
return -1 if len(arr) < k else nlargest(k, arr)[-1]Complexity
| Measure | Complexity |
|---|---|
| Time | O(n \times \log n) |
| Space | O(n) auxiliary |
Pattern: Tree Traversal
Choose the order — preorder, inorder, postorder, level — and the problem solves itself. LeetCode 2583. Kth Largest Sum in a Binary Tree is filed here because LeetCode tags it Tree and Binary Tree, which is the vocabulary this hub collects.
The tree traversal guide has the Python template for the pattern and the 225 LeetCode problems that use it.
Related problems
Frequently asked questions
- How hard is LeetCode 2583. Kth Largest Sum in a Binary Tree?
- LeetCode 2583. Kth Largest Sum in a Binary Tree is rated Medium on LeetCode.
- What is the time complexity of LeetCode 2583. Kth Largest Sum in a Binary Tree?
- The Python solution on this page runs in O(n \times \log n).
- What is the space complexity of LeetCode 2583. Kth Largest Sum in a Binary Tree?
- The Python solution on this page uses O(n) auxiliary space.
- What topics does LeetCode 2583. Kth Largest Sum in a Binary Tree cover?
- LeetCode 2583. Kth Largest Sum in a Binary Tree is tagged Tree, Breadth-First Search, Binary Tree and Sorting on LeetCode.