London | 25-SDC-July | Eyuel Abraham | Sprint 2 | Linked list implementation.

Sprint-2/implement_linked_list/linked_list.py

@@ -0,0 +1,47 @@
+class Node:
+    def __init__(self, value):
+        self.value = value
+        self.prev = None
+        self.next = None
+
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+
+    def push_head(self, value):
+        new_node = Node(value)
+        new_node.next = self.head
+        new_node.prev = None
+
+        if self.head is not None:
+            self.head.prev = new_node
+        self.head = new_node
+
+        if self.tail is None:
+            self.tail = new_node
+
+        return new_node
+
+    def pop_tail(self):
+        if self.tail is None:
+            return
+        node_to_be_removed = self.tail
+        self.remove(node_to_be_removed)
+        return node_to_be_removed.value
+
+    def remove(self, node):
+        if node.prev is not None:
+            node.prev.next = node.next
+        else:
+            self.head = node.next
+        if node.next is not None:
+            node.next.prev = node.prev
+        if node == self.tail:
+            self.tail = node.prev
+        node.prev = None
+        node.next = None
+
+
+
+