diff --git a/Sprint-2/implement_linked_list/linked_list.py b/Sprint-2/implement_linked_list/linked_list.py index e69de29b..e1970c67 100644 --- a/Sprint-2/implement_linked_list/linked_list.py +++ b/Sprint-2/implement_linked_list/linked_list.py @@ -0,0 +1,46 @@ +class Node: + def __init__(self, data): + self.data = data + self.next = None + self.previous = None + +class LinkedList: + def __init__(self): + self.head = None + self.tail = None + + def push_head(self, data): + new_node = Node(data) + if self.head is None: + self.head = new_node + self.tail = new_node + else: + new_node.next = self.head + self.head.previous = new_node + self.head = new_node + return new_node + + def remove(self, node): + if node is None: + return + if node == self.head: + self.head = node.next + if node == self.tail: + self.tail = node.previous + if node.previous is not None: + node.previous.next = node.next + if node.next is not None: + node.next.previous = node.previous + node.next = None + node.previous = None + + def pop_tail(self): + if self.tail is None: + return None + node_to_pop = self.tail + data = node_to_pop.data + self.remove(node_to_pop) + return data + + +