[leetcode: Python]206.Reverse Linked List

题目：
反转一个单链表

方法一：性能58ms

# Definition for singly-linked list.# class ListNode(object):#     def __init__(self, x):#         self.val = x#         self.next = Noneclass Solution(object):    def reverseList(self, head):        """        :type head: ListNode        :rtype: ListNode        """        #迭代        new_head = None        while head:            p = head            head = head.next            p.next = new_head            new_head = p        return new_head

方法二：性能52ms

# Definition for singly-linked list.# class ListNode(object):#     def __init__(self, x):#         self.val = x#         self.next = Noneclass Solution(object):    def reverseList(self, head):        """        :type head: ListNode        :rtype: ListNode        """        pre = None        cur = None         while head:             cur = head             head = head.next            cur.next = pre             pre = cur         return cur