题解 | 两个链表的第一个公共结点

from functools import total_ordering
from re import L
from operator import le
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

#
# 
# @param pHead1 ListNode类 
# @param pHead2 ListNode类 
# @return ListNode类
#
class Solution:
    def FindFirstCommonNode(self , pHead1 , pHead2 ):
        # write code here
        pHead1_length = 0
        pHead2_length = 0
        p = pHead1
        q = pHead2
        while(p):
            pHead1_length = pHead1_length + 1
            p=p.next
        while(q):
            pHead2_length = pHead2_length + 1
            q = q.next
        p = pHead1
        q = pHead2
        if pHead1_length< pHead2_length:
            p = pHead2
            q = pHead1
        index = abs(pHead1_length - pHead2_length)
        while(index>0):
            p=p.next
            index = index -1 
        while(p and q):
            if (p == q):
                return p
            p = p.next
            q = q.next
        
        return None