def swapPairs(head):
dummy = cur = Node(0)
cur.next = head
while cur.next and cur.next.next: # 从head 和 head的下一个 开始
p1 = cur.next
p2 = cur.next.next
p1.next = p2.next # p1 在 p2 前变化
p2.next = p1
cur.next = p2
# cur.next = p2
# p1.next = p2.next
# p2.next = p1
cur = cur.next.next
return dummy.next
lst = LinkedList()
lst.add_last(1)
lst.add_last(2)
lst.add_last(3)
lst.add_last(4)
lst.printlist()
lst.head.next = swapPairs(lst.head.next)
lst.printlist()
lst.head.next = swapPairs(lst.head.next)
lst.printlist()
node = node.next
return head
# 删除所有重复的,一个不留 Given 1->1->1->2->3, return 2->3.
def deleteDuplicates2(head):
dummy = pre = Node(0) # dummy 留着作为开头连接后面, pre去连接后面的
dummy.next = head # dummy和LL连接起来
while head and head.next:
if head.value == head.next.value:
while head and head.next and head.value == head.next.value:
head = head.next
head = head.next
pre.next = head
else:
pre = pre.next
head = head.next
return dummy.next
lst = LinkedList()
lst.add_last(1)
lst.add_last(3)
lst.add_last(3)
lst.add_last(3)
lst.add_last(5)
lst.add_last(7)
lst.add_last(7)
lst.add_last(9)
lst.head.next = deleteDuplicates2(lst.head.next)
lst.printlist()
# -*- coding:utf-8 -*-
"""
author: lijingxin
Created on 12:35 PM 4/25/20
"""
from util.LinkedList import LinkedList
from util.LinkedList import Node
def isPalindrome(head):
rev = None
slow = fast = head
while fast and fast.next:
fast = fast.next.next
rev, rev.next, slow = slow, rev, slow.next
if fast:
slow = slow.next
while rev and rev.value == slow.value: # 满足条件 slow往后移一个, rev往前移一个
slow = slow.next
rev = rev.next
return not rev
lst = LinkedList()
lst.add_last(1)
lst.add_last(3)
lst.add_last(5)
lst.add_last(7)
lst.add_last(9)
lst.printlist()
print(isPalindrome(lst.head.next))
lst.printlist()