题解 | #链表中环的入口结点#

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    def EntryNodeOfLoop(self, pHead):
        # write code here
        dic = set()
        h = pHead
        while h:
            if h in dic:
                return h
            dic.add(h)
            h = h.next
        return h