Manchester | 26-SDC-Jun | Fithi Teklom | Sprint 2 | Linked Link in Python

Sprint-2/implement_linked_list/linked_list.py

@@ -0,0 +1,56 @@
+
+from __future__ import annotations
+
+from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+
+class Node(Generic[T]):
+    __slots__ = ("value", "next", "previous")
+
+    def __init__(self, value: T) -> None:
+        self.value: T = value
+        self.next: Node[T] | None = None
+        self.previous: Node[T] | None = None
+
+
+class LinkedList(Generic[T]):
+    def __init__(self) -> None:
+        self.head: Node[T] | None = None
+        self.tail: Node[T] | None = None
+
+    def push_head(self, value: T) -> Node[T]:
+        new_node = Node(value)
+
+        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 pop_tail(self) -> T | None:
+        if self.tail is None:
+            return None
+
+        value = self.tail.value
+        self.remove(self.tail)
+        return value
+
+    def remove(self, node: Node[T]) -> None:
+        if node.previous is not None:
+            node.previous.next = node.next
+        else:
+            self.head = node.next
+
+        if node.next is not None:
+            node.next.previous = node.previous
+        else:
+            self.tail = node.previous
+
+        node.next = None
+        node.previous = None