# 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
nodes=set()
while pHead1 is not None:
nodes.add(pHead1)
pHead1=pHead1.next
while pHead2 is not None:
if pHead2 not in nodes:
pHead2=pHead2.next
else:
return pHead2
return None
##### 利用希哈表来存储pHead1的所有节点,在遍历pHead2的节点,判断pHead2的节点是否在希哈表中,
在的时候就是第一个公共节点,return 该节点即可。