collections을 이용
from typing import List, Deque
import collections
class ListNode:
def __init__(self, val=0, next=None):
self.val = val
self.next = next
def isPalidrome(self, head:ListNode) -> bool:
q: List = []
if not head:
return True
node = head
while node is not None:
q.append(node.val)
node = node.next
while len(q) > 1:
if q.pop(0) != q.pop():
return False
def isPalidrome_deque(self, head:ListNode) -> bool:
q: Deque = collections.deque()
if not head:
return True
node = head
while node is not None:
q.append(node.val)
node = node.next
while len(q) > 1:
if q.popleft() != q.pop():
return False
return True
Runner 기법을 사용
def isPalindrome_runner(self, head: ListNode) -> bool:
rev = None
slow = fast = head
while fast and fast.next:
fast = fast.next.next
rev, rev.next, slow = slow, rev, slow.next
if fast:
slow = slow.next
while rev and rev.val == slow.val:
slow, rev = slow.next, rev.next
return not rev