剑指offer--面试题37：两个链表的第一个公共结点

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题目描述

输入两个链表，找出它们的第一个公共结点。

python实现：

# -*- coding:utf-8 -*-class ListNode:    def __init__(self, x):        self.val = x        self.next = Noneclass Solution:    def FindFirstCommonNode(self, pHead1, pHead2):        # write code here        if pHead1 is None or pHead2 is None:            return None        len1, len2 = self.getLen(pHead1), self.getLen(pHead2)        #让head1指向更短的链表        if len1>len2:            pHead1, pHead2 = pHead2, pHead1            len1, len2 = len2, len1                     gap = len2-len1        p1 = pHead1        p2 = pHead2        while gap:            p2 = p2.next            gap -= 1                 while p1:            if p1!=p2:                p1=p1.next                p2=p2.next            else:                return p1        return None                          def getLen(self, head):        if head is None:            return 0        p = head        cnt = 0        while p:            cnt += 1            p = p.next        return cnt

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