题目
输入两个链表，找出它们的第一个公共结点。
思路
用两个指针，当它们指向链表末尾时，再从另一个头结点开始遍历。
代码
# -*- coding:utf-8 -*-
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def FindFirstCommonNode(self, pHead1, pHead2):
# write code here
node1 = pHead1; node2 = pHead2
while node1 != node2:
node1 = pHead2 if not node1 else node1.next
node2 = pHead1 if not node2 else node2.next
return node1