理论上好像应该BFS+size k的minheap
但我览
对不起
反正差不多
def kthLargestLevelSum(self, root: Optional[TreeNode], k: int) -> int:
mp = defaultdict(int)
def dfs(root, level):
if root is None:
return
mp[level] += root.val
dfs(root.left, level+1)
dfs(root.right, level+1)
dfs(root,0)
l = []
for _,v in mp.items():
l.append(v)
l.sort()
return -1 if k>len(l) else l[-k]