Added data structure

AllAlgorithms · Vishesh-dd4723 · Oct 1, 2021 · Oct 1, 2021 · 6fbcd9fe4fff6d732f618b78255ad28d281cb40e
commit 6fbcd9fe4fff6d732f618b78255ad28d281cb40e
diff --git a/algorithms/data-structures/linked-lists/doubly linked list.py b/algorithms/data-structures/linked-lists/doubly linked list.py
@@ -0,0 +1,52 @@
+class Node:
+    def __init__(self, value):
+        self.value = value
+        self.next = None
+        self.prev = None
+
+class DoublyLinkedList:
+    def __init__(self, object):
+        self.tail = self.head = Node(object)
+
+    def append(self, object):
+        c = self.tail
+        self.tail.next = Node(object)
+        self.tail = self.tail.next
+        self.tail.prev = c
+
+    def insert(self, index, object):
+        new_node = Node(object)
+        if index == 0:
+            ll = new_node
+            self.head.prev = ll
+            ll.next = self.head
+            self.head = ll
+        else:
+            current_indx = 0
+            ll = self.head
+            while current_indx < index - 1:
+                ll = ll.next
+                current_indx += 1
+            ll.next.prev = new_node
+            new_node.next = ll.next
+            ll.next = new_node
+            new_node.prev = ll
+
+    def pop(self):
+        curr = self.head
+        while curr.next.next != None:
+            curr = curr.next
+        self.tail = curr
+        self.tail.next = None
+
+    def show(self, reverse = False):
+        if reverse:
+            curr = self.tail
+            while curr:
+                print(curr.value)
+                curr = curr.prev
+        else:
+            curr = self.head
+            while curr:
+                print(curr.value)
+                curr = curr.next
diff --git a/algorithms/data-structures/queue/queue.py b/algorithms/data-structures/queue/queue.py
@@ -0,0 +1,43 @@
+class Node():
+    def __init__(self, data):
+        self.data = data
+        self.next = None
+        self.prev = None
+
+class Queue():
+    def __init__(self):
+        self.tail = self.head = None
+        self.length = 0
+
+    def insert(self, object):
+        if self.length == 0:
+            self.tail = self.head = Node(object)
+        else:
+            c = Node(object)
+            self.head.prev = c
+            c.next = self.head
+            self.head = c
+        self.length += 1
+
+    def pop(self):
+        if self.length == 1:
+            value = self.tail.data
+            self.tail = self.head = None
+        else:
+            c = self.tail.prev
+            value = self.tail.data
+            c.next = None
+            self.tail = c
+        self.length -= 1
+        return value
+
+    def isEmpty(self):
+        return not bool(self.length)
+
+    def show(self):
+        curr = self.head
+        lst = []
+        while curr:
+            lst.append(curr.data)
+            curr = curr.next
+        return lst