Leetcode #206 Reverse Linked List

Description

Reverse a singly linked list.

Code

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

class Solution(object):
    def reverseList(self, head):
        """
        :type head: ListNode
        :rtype: ListNode
        """
        if not head:
            return head
        pre = None
        cur = head
        h = head
        while cur:
            h = cur
            tmp = cur.next
            cur.next = pre
            pre = cur
            cur = tmp
        return h