剑指Offer55：链表中环的入口结点

思路：

# -*- coding:utf-8 -*-
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None
class Solution:
    def EntryNodeOfLoop(self, pHead):
        # write code here
        #遍历链表，环的存在，遍历遇见的第一个重复的即为入口节点
        tempList = []
        p = pHead
        while p:
            if p in tempList:
                return p
            else:
                tempList.append(p)
            p = p.next