def palindrome(alist):
head = alist.head
if head == None:
return head
#1.find mid point
fast = head.next
slow = head
while fast is not None and fast.next is not None:
fast = fast.next.next
slow = slow.next
#2.split into two linklist
head2 = Node()
if fast == None:
head2.next = slow.next
slow.next = None
else:
head2.next = slow.next.next
slow.next = None
#3.reverse second linklist
pre = None
cur = head2.next
while cur:
temp = cur.next
cur.next = pre
pre = cur
cur = temp
# judging if it is palindrome
while pre.next is not None:
if pre.value != head.next.value:
return False
else:
pre = pre.next
head = head.next
return True
def LinkListtoBST(head):
if head is None:
return None
dummy = Node(0)
dummy.next = head
fast = dummy
slow = dummy
slow_tail = dummy
while fast is not None and fast.next is not None:
fast = fast.next.next
slow_tail = slow
slow = slow.next
slow_tail.next = None
node = Nd(slow.value)
node._left = LinkListtoBST(dummy.next)
node._right = LinkListtoBST(slow.next)
return node
slow_tail = dummy
while fast is not None and fast.next is not None:
fast = fast.next.next
slow_tail = slow
slow = slow.next
slow_tail.next = None
node = Nd(slow.value)
node._left = LinkListtoBST(dummy.next)
node._right = LinkListtoBST(slow.next)
return node
if __name__ == '__main__':
node1 = Node(1)
node2 = Node(2)
node3 = Node(3)
node4 = Node(4)
node5 = Node(5)
node6 = Node(6)
node1.next = node2
node2.next = node3
node3.next = node4
node4.next = node5
node5.next = node6
bst = BinarySearchTree()
result = LinkListtoBST(node1)
bst._root = result
bst.print_inorder()
if node.next is None:
return node
head = reverse_recursion(node.next)
node.next.next = node
node.next = None
return head
if __name__ == '__main__':
ll = LinkList()
ll.add_last(1)
ll.add_last(2)
ll.add_last(3)
ll.add_last(4)
ll.print_list()
print()
reverse_l(ll)
ll.print_list()
print()
node1 = Node(1)
node2 = Node(2)
node3 = Node(3)
node4 = Node(4)
node1.next = node2
node2.next = node3
node3.next = node4
result = reverse_recursion(node1)
l2 = LinkList()
l2.head.next = result
l2.print_list()
ll_a.add_last(1)
ll_a.add_last(3)
ll_a.add_last(5)
ll_a.add_last(7)
ll_b = LinkList()
ll_b.add_last(2)
ll_b.add_last(4)
ll_b.add_last(5)
ll_b.add_last(8)
ll_b.add_last(10)
ll_b.add_last(12)
node1 = Node(1)
node2 = Node(3)
ndoe3 = Node(5)
node1.next = node2
node2.next = ndoe3
node_a = Node(2)
node_b = Node(4)
node_c = Node(5)
node_d = Node(8)
node_a.next = node_b
node_b.next = node_c
node_c.next = node_d
#result = merge_list(node1, node_a)
#ll = LinkList()
#ll.head.next = result
#ll.print_list()
#print()
def find_cycle(llist):
return find_cycle_helper(llist.head)
def find_cycle_helper(head):
if head is None:
return False
fast = head
slow = head
while fast is not None and fast.next is not None:
fast = fast.next.next
slow = slow.next
if slow == fast:
return True
return False
if __name__ == '__main__':
node1 = Node(1)
node2 = Node(2)
node3 = Node(3)
node1.next = node2
node2.next = node3
node3.next = node1
result = find_cycle_helper(node1)
print(result)
b = b.next if b else head_a
return a.value
if __name__ == '__main__':
a1 = Node(1)
a2 = Node(3)
a3 = Node(5)
c1 = Node(9)
c2 = Node(10)
c3 = Node(11)
b1 = Node(2)
b2 = Node(4)
b3 = Node(6)
b4 = Node(8)
a1.next = a2
a2.next = a3
a3.next = c1
c1.next = c2
c2.next = c3
b1.next = b2
b2.next = b3
b3.next = b4
b4.next = c1
result = find_same(a1, b1)
print(result)
result2 = find_same2(a1, b1)
print(result2)