算法题 Determine If Linked List is Palindrome

Hi, here's your problem today. This problem was recently asked by Microsoft:

You are given a doubly linked list. Determine if it is a palindrome.

Can you do this for a singly linked list?

class Node(object):

  def __init__(self, val):

    self.val = val

    self.next = None

    self.prev = None



def is_palindrome(node):

  # Fill this in.



node = Node('a')

node.next = Node('b')

node.next.prev = node

node.next.next = Node('b')

node.next.next.prev = node.next

node.next.next.next = Node('a')

node.next.next.next.prev = node.next.next



print is_palindrome(node)

# True