98. Sort List/148. Sort List
- 本题难度: Medium
- Topic: Linked List
Description
Sort a linked list in O(n log n) time using constant space complexity.
Example
Example 1:
Input: 1->3->2->null
Output: 1->2->3->null
Example 2:
Input: 1->7->2->6->null
Output: 1->2->6->7->null
Challenge
Solve it by merge sort & quick sort separately.
Challenge
Can you do this in-place without altering the nodes‘ values?
我的代码
class Solution(object):
def merge(self,x,y):
pos = ListNode(0)
res = pos
while(x and y):
if x.val<y.val:
pos.next = x
x = x.next
else:
pos.next = y
y = y.next
pos = pos.next
pos.next = x or y
return res.next
def sortList(self,head):
if not head or not head.next:
return head
pre,slow,fast = None, head,head
while fast and fast.next:
pre,slow,fast = slow,slow.next,fast.next.next
pre.next = None# 保证第一列始终不长于第二列
return self.merge(*map(self.sortList,(head,slow)))
思路
采用归并排序
- 时间复杂度 O(nlog(n))
原文地址:https://www.cnblogs.com/siriusli/p/10376473.html
时间: 2024-10-06 13:09:00