from single_linked_list import Node, LinkedList
def is_palindrome(self):
fast = self.head
slow = self.head
stack = []
while fast and fast.next:
fast = fast.next.next
slow = slow.next
stack.append(slow.val)
if not fast:
stack.pop()
slow = slow.next
while slow and stack.pop() == slow.val:
slow = slow.next
return (True if not slow else False)
setattr(LinkedList, 'is_palindrome', is_palindrome)
val_list_1 = [1, 2, 3, 4, 5]
linked_list_1 = LinkedList.from_val_list(val_list_1)
print linked_list_1.is_palindrome()
val_list_2 = [1, 2, 3, 2, 1]
linked_list_2 = LinkedList.from_val_list(val_list_2)
print linked_list_2.is_palindrome()
from single_linked_list import Node, LinkedList
def is_palindrome(self):
fast = self.head
slow = self.head
stack = []
while fast and fast.next:
fast = fast.next.next
slow = slow.next
stack.append(slow.val)
if not fast:
stack.pop()
slow = slow.next
while slow and stack.pop() == slow.val:
slow = slow.next
return (True if not slow else False)
setattr(LinkedList, 'is_palindrome', is_palindrome)
val_list_1 = [1, 2, 3, 4, 5]
linked_list_1 = LinkedList.from_val_list(val_list_1)
print linked_list_1.is_palindrome()
val_list_2 = [1, 2, 3, 2, 1]
linked_list_2 = LinkedList.from_val_list(val_list_2)
print linked_list_2.is_palindrome()
from single_linked_list import Node, LinkedList
def kth_to_last(self, k):
fast = self.head
slow = self.head
for i in xrange(k):
fast = fast.next
while fast.next:
fast = fast.next
slow = slow.next
return slow
setattr(LinkedList, 'kth_to_last', kth_to_last)
val_list = [1, 2, 3, 4, 5]
linked_list = LinkedList.from_val_list(val_list)
print linked_list
k = 2
print 'the {k}th to last is {node}'.format(k=k, node=linked_list.kth_to_last(k))
from single_linked_list import Node, LinkedList
def loop_head(self):
fast = self.head
slow = self.head
while fast and fast.next:
fast = fast.next.next
slow = slow.next
if fast == slow:
break
if not fast or not fast.next:
return None
p0 = self.head
p1 = fast
while p0 != p1:
p0 = p0.next
p1 = p1.next
return p0
setattr(LinkedList, 'loop_head', loop_head)
val_list = [1, 2, 3, 4, 5]
linked_list = LinkedList.from_val_list(val_list)
linked_list.last().next = linked_list.head.next.next.next
print linked_list.loop_head().val
