Leetcode "insertion Sort List" Python implementation

title :

Sort a linked list using insertion sort.

code : OJ Test via runtime:860 ms

1 #Definition for singly-linked list.2 #class ListNode:3 #def __init__ (self, x):4 #self.val = x5 #Self.next = None6 7 classSolution:8     #@param head, a listnode9     #@return a ListNodeTen     definsertionsortlist (Self, head): One          A          -         ifHead isNoneorHead.next isNone: -             returnHead the          -Dummyhead =listnode (0) -Dummyhead.next =Head -          +Curr =Dummyhead.next -          whileCurr.next is  notNone: +             ifCurr.next.val <Curr.val: APre =Dummyhead at                  whilePre.next.val <Curr.next.val: -Pre =Pre.next -TMP =Curr.next -Curr.next =Tmp.next -Tmp.next =Pre.next -Pre.next =tmp in             Else: -Curr =Curr.next to          +         returnDummyhead.next

Ideas :

The first thing to know is the principle of insertion sorting.

For a single-linked list, pointers need to be exchanged.

Small white memory insertion sorting principle only one sentence: analogy poker cards, the cards by size inserted.

The place to be aware of IS

Do not add extra judgment, otherwise it will time out; the first time I run, I add a pre! = Curr to the inside of the while loop condition, and the result is timed out.

Check the logic and find that it is useless to judge a waste of time, removed and passed.

Leetcode "insertion Sort List" Python implementation