题目大意
通过插入排序的方法排序一个链表。
解题思路
参考:http://www.cnblogs.com/zuoyuan/p/3700105.html
代码
class Solution(object):
def insertionSortList(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
if not head:
return head
dummy = ListNode(0)
dummy.next = head
curr = head
while curr.next:
if curr.next.val < curr.val: # 直到某数小于其前面的数,进入
pre = dummy # 回到头开始往后遍历
while pre.next.val < curr.next.val: # 用pre直到找到应该插入的位置
pre = pre.next
# 如上图
tmp = curr.next
curr.next = tmp.next
tmp.next = pre.next
pre.next = tmp
else:
curr = curr.next
return dummy.next