题解 | #牛牛的二叉树问题#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param root TreeNode类 
# @param target double浮点型 
# @param m int整型 
# @return int整型一维数组
#
import heapq
import math
class Solution:
    def findClosestElements(self , root: TreeNode, target: float, m: int) -> List[int]:
        # write code here
        res = list()
        heap = []
        def dfs(node):
            if not node:
                return None
            # 首先递归处理左子节点
            dfs(node.left)
            dfs(node.right)
            current_val = node.val 
            if current_val:
                heapq.heappush(heap, (abs(current_val - target), current_val))         
            return node.val

        dfs(root)
        while m > 0:
            if heap:
               val = heapq.heappop(heap)[1]
               res.append(val)
            m -= 1
        res.sort()
        return res