Insertion Sort List Leetcode Python

链表插入排序

原创于 2015-01-21 23:37:51 发布 · 454 阅读

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#python #leetcode #linklist

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本文介绍了一种使用插入排序算法对链表进行排序的方法。通过在链表中找到不匹配排序顺序的位置，并将其调整到正确的位置来实现排序。适用于理解链表操作及排序算法。

Sort a linked list using insertion sort.

It is an insertion sort problem, we can treat it like sort array with insertion sort.

The main idea is to find the spot that mismatch the order.

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    # @param head, a ListNode
    # @return a ListNode
    def insertionSortList(self, head):
        if head==None or head.next==None:
            return head
        dummy=ListNode(0) #dummy head
        dummy.next=head
        cur=head
        while cur.next:
            if cur.next.val<cur.val: #if mismatch
                pre=dummy # start sort from the head
                while pre.next.val<cur.next.val:# find the spot to swop
                    pre=pre.next
                tmp=cur.next
                cur.next=tmp.next
                tmp.next=pre.next
                pre.next=tmp
            else:
                cur=cur.next
        return dummy.next