diff --git a/Sprint-2/implement_linked_list/linked_list.py b/Sprint-2/implement_linked_list/linked_list.py index e69de29..46d0ac0 100644 --- a/Sprint-2/implement_linked_list/linked_list.py +++ b/Sprint-2/implement_linked_list/linked_list.py @@ -0,0 +1,45 @@ +class Node: + def __init__(self, value): + self.value = value + self.next = None + self.previous = None + +class LinkedList: + def __init__(self): + self.head = None + self.tail = None + + def push_head(self, value): + node = Node(value) + node.next = self.head + if self.head: + self.head.previous = node + self.head = node + if self.tail is None: + self.tail = node + return node + + def pop_tail(self): + if self.tail is None: + return None + node = self.tail + value = node.value + if node.previous: + self.tail = node.previous + self.tail.next = None + else: + self.head = None + self.tail = None + return value + + def remove(self, node): + if node.previous: + node.previous.next = node.next + else: + self.head = node.next + if node.next: + node.next.previous = node.previous + else: + self.tail = node.previous + node.next = None + node.previous = None