题解 | #两个链表的第一个公共结点#

# -*- 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
        cur1=pHead1
        cur2=pHead2
        j=0
        while True:
            if cur1:
                j=j+1
                cur1=cur1.next
            else:
                break
        while True:
            if cur2:
                j=j-1
                cur2=cur2.next
            else:
                break
        cur1=pHead1
        cur2=pHead2
        if j>0:   #此时j为两个链表长度差
            for i in range(j):
                cur1=cur1.next  #使两个链表长度相等，移动j次后使cur1与cur2在相同位置
        elif j<0:
            j=abs(j)
            for i in range(j):
                cur2=cur2.next
        else: #j=0
            cur1=pHead1
            cur2=pHead2
             
        while True:
            if cur1 == cur2:
                return cur1
            else:
                 cur1=cur1.next
                 cur2=cur2.next