"""
Sep 4, 2018
"""
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def reverseList(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
"""
思路:
a -> b -> c
1. 加上 tail 指標: tail = None
None a -> b -> c
2. 處理 node 前有甚麼事情需要做? 我們需要下個node位置
cur = head
head = cur.next
cur.next = tail
tail = cur
"""
tail = cur = None
while head:
cur = head
head = cur.next
cur.next = tail
tail = cur
return cur
