Re: [閒聊] 每日leetcode

[dont (dont)]

2583. Kth Largest Sum in a Binary Tree

## 思路

BFS計算每層的總和, 丟到 k-size的min-heap

## Code

```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:

        heap = []
        queue = deque([root])
        while queue:
            curr = 0
            for _ in range(len(queue)):
                node = queue.popleft()
                curr += node.val
                if node.left:
                    queue.append(node.left)
                if node.right:
                    queue.append(node.right)
            heapq.heappush(heap, curr)
            if len(heap) > k:
                heapq.heappop(heap)

        return -1 if len(heap) < k else heap[0]
```

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