题解 | #两个链表的第一个公共结点#

# 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
        hash_set = set()
        while pHead1:
            hash_set.add(pHead1)
            pHead1 = pHead1.next
        while pHead2:
            if pHead2 in hash_set:
                return pHead2
            pHead2 = pHead2.next
        return None