def test_is_palindrome(self):
s = palindromeLinkedList.Solution()
node1 = ListNode(1)
node1.next = ListNode(2)
self.assertEqual(s.isPalindrome(node1), False)
node2 = ListNode(1)
node2.next = ListNode(2)
node2.next.next = ListNode(2)
node2.next.next.next = ListNode(1)
self.assertEqual(s.isPalindrome(node2), True)
def test_linked_list_cycle(self):
s = linkedListCycle.Solution()
node = ListNode(3)
node.next = ListNode(2)
node.next.next = ListNode(0)
end_node = ListNode(-4)
end_node.next = node.next
node.next.next.next = end_node
self.assertEqual(s.hasCycle(node), True)
node2 = ListNode(1)
self.assertEqual(s.hasCycle(node2), False)
def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
newHead = ListNode(-1)
newHead.next = head
begin = newHead # m-1 处
# 遍历到逆转的起来
i = 1
while i < m:
begin, i = begin.next, i + 1
cur = begin.next
start = begin.next # m 处
pre = None
while i <= n:
tp, cur.next = cur.next, pre
pre, cur, i = cur, tp, i + 1
begin.next = pre
if start:
start.next = cur
return newHead.next
def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
newHead = ListNode(-1)
cur = newHead
while l1 or l2:
while l1:
if l2 and l1.val > l2.val:
break
cur.next = l1
cur, l1 = cur.next, l1.next
while l2:
if l1 and l2.val > l1.val:
break
cur.next = l2
cur, l2 = cur.next, l2.next
return newHead.next
def mergeTwoLists2(self, l1: ListNode, l2: ListNode) -> ListNode:
newHead = ListNode(-1)
cur = newHead
while l1 and l2:
if l1.val < l2.val:
cur.next, l1 = l1, l1.next
else:
cur.next, l2 = l2, l2.next
cur = cur.next
while l1:
cur.next, l1 = l1, l1.next
cur = cur.next
while l2:
cur.next, l2 = l2, l2.next
cur = cur.next
return newHead.next
if l1 and l2.val > l1.val:
break
cur.next = l2
cur, l2 = cur.next, l2.next
return newHead.next
def mergeTwoLists2(self, l1: ListNode, l2: ListNode) -> ListNode:
newHead = ListNode(-1)
cur = newHead
while l1 and l2:
if l1.val < l2.val:
cur.next, l1 = l1, l1.next
else:
cur.next, l2 = l2, l2.next
cur = cur.next
while l1:
cur.next, l1 = l1, l1.next
cur = cur.next
while l2:
cur.next, l2 = l2, l2.next
cur = cur.next
return newHead.next
l1 = ListNode(-9)
l1.next = ListNode(3)
l2 = ListNode(5)
l2.next = ListNode(7)
s = Solution()
s.mergeTwoLists2(l1, l2)
while i < m:
begin, i = begin.next, i + 1
cur = begin.next
start = begin.next # m 处
pre = None
while i <= n:
tp, cur.next = cur.next, pre
pre, cur, i = cur, tp, i + 1
begin.next = pre
if start:
start.next = cur
return newHead.next
s = Solution()
n5 = ListNode(5)
n4 = ListNode(4)
n4.next = n5
n3 = ListNode(3)
n3.next = n4
n2 = ListNode(2)
n2.next = n3
n1 = ListNode(1)
n1.next = n2
s = Solution()
r: list = s.reverseBetween(n1, 2, 4)
string = "["
if r:
string += str(r.val)
r = r.next
while r:
fast = head.next
while fast and fast.next:
slow, fast = slow.next, fast.next.next
cur = slow.next
slow.next = None
# 反转后半部分
pre = None
while cur:
tp, cur.next = cur.next, pre
pre, cur = cur, tp
# 重新合并两段
left = head
right = pre
while left and right:
tp_right = right.next
right.next, left.next = left.next, right
left, right = right.next, tp_right
return head
l = ListNode(1)
l.next = ListNode(2)
l.next.next = ListNode(3)
l.next.next.next = ListNode(4)
l.next.next.next.next = ListNode(5)
s = Solution()
r = s.reorderList(l)
r.print()
# coding=utf-8
"""
@project : algorithmPython
@ide : PyCharm
@file : reverseList
@author : illusion
@desc : 206. 反转链表 https://leetcode-cn.com/problems/reverse-linked-list/
@create : 2020-10-18 15:20:14
"""
from listNode.model import ListNode
class Solution:
def reverseList(self, head: ListNode) -> ListNode:
if not head:
return None
pre = None
while head:
tp, head.next = head.next, pre
pre, head = head, tp
return pre
n3 = ListNode(3)
n2 = ListNode(2)
n2.next = n3
n1 = ListNode(1)
n1.next = n2
s = Solution()
s.reverseList(n1)