# Definition for singly-linked list.
# class ListNode(object):
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution(object):
def isPalindrome(self, head):
"""
:type head: ListNode
:rtype: bool
"""
if not head :
return True
if not head.next :
return True
else :
slow = fast = head
while fast.next and fast.next.next:
slow = slow.next
fast = fast.next.next
head2 = slow.next
dummyHead = ListNode(0)
dummyHead.next = head2
p = head2.next
head2.next = None
while p:
nextP = p.next
p.next = dummyHead.next
dummyHead.next = p
p = nextP
p1 =head
head2 = dummyHead.next
p2 = head2
while p2:
if p1.val == p2.val:
p1 = p1.next
p2 = p2.next
else:
return False
return True