36.两个链表的第一个公共结点(python)

题目描述

输入两个链表，找出它们的第一个公共结点。

 class Solution:
     def FindFirstCommonNode(self, pHead1, pHead2):
         # write code here
         if pHead1==pHead2:
             return pHead1
         p1 = pHead1
         p2 = pHead2
         flag=1
         while p1 and p2 !=None:
             p1 = p1.next
             p2 = p2.next
         if p1 == None:
             flag=2
             p1 = p2
         k=0
         while p1:   #计算两个链表的长度差
             k+=1
             p1=p1.next
         if flag==1:  #flag记录长的那个链表
             while k>0:
                 pHead1=pHead1.next
                 k-=1    #先走k步
         else:
             while k >0:
                 pHead2=pHead2.next
                 k-=1
         while pHead1 and pHead2:
             if pHead1==pHead2:
                 return pHead1
             pHead1=pHead1.next
             pHead2=pHead2.next
         return None

2019-12-25 10:39:02