Leetcode 147. Insertion Sort List (python version)

Topic:

sort a linked list using insertion sort.

The main idea is to implement a list of insert sort

algorithm idea:

     one node

For each node with the idea of inserting a sort into the new ascending list of lists

Here's a small trick,leetcode that has a set of data that is 1~4999 ascending sequence if we use the above method will time out

So we set a last bit when we insert the sort, and we record where we are currently inserted.

At the next insertion time compared to the last insertion position, if the current Node.val > Last.val, then we can only start from the previous lookup, because the preceding node Val is smaller than the nodes Val, there is no need to find.

Code:

Class solution (object):     def addinlist (Self, head, last, node):         iterator = head         if last.val <= node.val:             iterator = last        while  iterator.next:            if  iterator.next.val > node.val:                 node.next = iterator.next                 iterator.next = node                 return iterator           &nBsp; iterator = iterator.next        iterator.next  = node        return iterator     Def insertionsortlist (Self, head):         "" "         :type head: ListNode         :rtype: ListNode         "" "         if head == None or head.next == None:             return head         start = listnode ( -2147483648)         last =  start        while head:             next = head.next             head.next = none            last =  self.addinlist (Start, last, head)              head = next        return start.next

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Leetcode 147. Insertion Sort List (python version)