while fast and fast.next_node:
fast = fast.next_node.next_node
slow = slow.next_node
pos += 1
ll2 = SinglyLinkedList()
ll2.head.next_node = slow
ll2.reverse_all2()
origin_head = ll.head.next_node
reverse_head = ll2.head.next_node
is_pal = True
while origin_head and reverse_head:
if origin_head.data == reverse_head.data:
origin_head = origin_head.next_node
reverse_head = reverse_head.next_node
else:
is_pal = False
break
return is_pal
if __name__ == '__main__':
# the result should be False, True, True, True, True
test_str_arr = ['abcdabc', 'aa', 'aba', 'abba', 'abcba']
for str in test_str_arr:
ll = SinglyLinkedList()
for s in str:
ll.insert_to_head(s)
print(is_palindrome(ll))
