London | 25-SDC-July | Andrei Filippov | Sprint 2 | Implement a linked list in Python

Sprint-2/implement_linked_list/linked_list.py

@@ -0,0 +1,50 @@
+class LinkedList:
+    def __init__(self):
+        self.head = None
+        self.tail = None
+
+    def push_head(self, element):
+        node = Node(element)
+        if self.head and self.tail:
+            node.next = self.head
+            self.head.previous = node
+            self.head = node
+        elif not self.head and not self.tail:
+            self.head = node
+            self.tail = node
+        return node
+
+    def pop_tail(self):
+        node = self.tail
+        if self.tail is not self.head:
+            self.tail = node.previous
+            node.previous.next = None
+            node.previous = None
+        else:
+            self.head = None
+            self.tail = None
+        return node.value
+
+    def remove(self, node):
+        if self.head != node and self.tail != node:
+            node.previous.next = node.next
+            node.next.previous = node.previous
+            node.previous, node.next = None, None
+        elif self.head == node and self.tail != node:
+            node.next.previous = None
+            self.head = node.next
+            node.previous, node.next = None, None
+        elif self.head != node and self.tail == node:
+            node.previous.next = None
+            self.tail = node.previous
+            node.previous, node.next = None, None
+        elif self.head == node and self.tail == node:
+            self.head = None
+            self.tail = None
+
+
+class Node:
+    def __init__(self, value):
+        self.value = value
+        self.previous = None
+        self.next = None