题解 | #链表中环的入口结点#
链表中环的入口结点
http://www.nowcoder.com/practice/253d2c59ec3e4bc68da16833f79a38e4
# -*- coding:utf-8 -*-
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def EntryNodeOfLoop(self, pHead):
# write code here
slow = pHead
fast = pHead
cur = pHead
while fast != None and fast.next != None:
slow = slow.next
fast = fast.next.next
if slow ==fast:
while slow != cur:
slow = slow.next
cur = cur.next
return cur
return None
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def EntryNodeOfLoop(self, pHead):
# write code here
slow = pHead
fast = pHead
cur = pHead
while fast != None and fast.next != None:
slow = slow.next
fast = fast.next.next
if slow ==fast:
while slow != cur:
slow = slow.next
cur = cur.next
return cur
return None
