147. Insertion Sort List

插入结点 但是 超时了。。

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

class Solution(object):
    def insertionSortList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if not head or not head.next:
            return head
        dummy = ListNode(0)
        dummy.next = ListNode(head.val)
        p = head.next
        while p:
            m = p.next
            q = dummy
            while q.next and p.val > q.next.val:
                q = q.next
            p.next = q.next
            q.next = p
            p = m
        return dummy.next    

嗯 很蠢的做法

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

class Solution(object):
    def insertionSortList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if not head or not head.next:
            return head
        stack = []
        p = head
        while p:
            stack.append(p.val)
            p = p.next
        stack.sort()
        dummy = ListNode(0)
        q = dummy
        while stack:
            q.next = ListNode(stack.pop(0))
            q = q.next
        return dummy.next

不超时的做法：

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

class Solution(object):
    def insertionSortList(self, head):
        p = dummy = ListNode(0)
        cur = dummy.next = head
        while cur and cur.next:
            val = cur.next.val
            if cur.val < val:
                cur = cur.next
                continue
            if p.next.val > val:
                p = dummy
            while p.next.val < val:
                p = p.next
            new = cur.next
            cur.next = new.next
            new.next = p.next
            p.next = new
        return dummy.next