leetcode 310 最小高度树 python

评论区说容易超时，就使用了字典和最小堆来进行加速

import heapq
class Solution(object):
    def findMinHeightTrees(self, n, edges):
        if n==1:
            return [0]
        dict_nei={}
        for e in edges:
            dict_nei[e[0]] = [e[1]] if e[0] not in dict_nei else dict_nei[e[0]]+[e[1]]
            dict_nei[e[1]] = [e[0]] if e[1] not in dict_nei else dict_nei[e[1]]+[e[0]]
        hq=[]
        for nei in dict_nei:
            heapq.heappush(hq,(len(dict_nei[nei]),nei,dict_nei[nei]))
        while len(dict_nei.keys())>=3:
            node_neis=[]
            while hq[0][0]==1:
                _,node,neis=heapq.heappop(hq)
                del dict_nei[node]
                node_neis.append((node,neis))
            for node,neis in node_neis:
                for nei in neis:
                    dict_nei[nei].remove(node)
                    heapq.heappush(hq,(len(dict_nei[nei]),nei,dict_nei[nei]))
        return dict_nei.keys()