Leetcode - 链表专题 - 148

在 O(n log n) 时间复杂度和常数级空间复杂度下，对链表进行排序。

示例 1:

输入: 4->2->1->3
输出: 1->2->3->4

示例 2:

输入: -1->5->3->4->0
输出: -1->0->3->4->5

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

class Solution(object):
    def sortList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        data = []
        while head:
            data.append(head.val)
            head = head.next
        data.sort()
        ptr = ListNode(0)
        ptr1 = ptr
        for item in data:
            ptr.next = ListNode(item)
            ptr = ptr.next
        return ptr1.next