Create python program to convert binary tree to double linked list .py

python program to convert binary tree to double linked list .py

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+#Represent a node of binary tree    
+class Node:    
+    def __init__(self,data):    
+        self.data = data;    
+        self.left = None;    
+        self.right = None;    
+
+class BinaryTreeToDLL:    
+    def __init__(self):    
+        #Represent the root of binary tree    
+        self.root = None;    
+        #Represent the head and tail of the doubly linked list    
+        self.head = None;    
+        self.tail = None;    
+
+    #convertbtToDLL() will convert the given binary tree to corresponding doubly linked list    
+    def convertbtToDLL(self, node):    
+        #Checks whether node is None    
+        if(node == None):    
+            return;    
+
+        #Convert left subtree to doubly linked list    
+        self.convertbtToDLL(node.left);    
+
+        #If list is empty, add node as head of the list    
+        if(self.head == None):    
+            #Both head and tail will point to node    
+            self.head = self.tail = node;    
+        #Otherwise, add node to the end of the list    
+        else:    
+            #node will be added after tail such that tail's right will point to node    
+            self.tail.right = node;    
+            #node's left will point to tail    
+            node.left = self.tail;    
+            #node will become new tail    
+            self.tail = node;    
+
+        #Convert right subtree to doubly linked list    
+        self.convertbtToDLL(node.right);    
+
+    #display() will print out the nodes of the list    
+    def display(self):    
+        #Node current will point to head    
+        current = self.head;    
+        if(self.head == None):    
+            print("List is empty");    
+            return;    
+        print("Nodes of generated doubly linked list: ");    
+        while(current != None):    
+            #Prints each node by incrementing pointer.    
+            print(current.data),    
+            current = current.right;    
+
+
+bt = BinaryTreeToDLL();    
+#Add nodes to the binary tree    
+bt.root = Node(1);    
+bt.root.left = Node(2);    
+bt.root.right = Node(3);    
+bt.root.left.left = Node(4);    
+bt.root.left.right = Node(5);    
+bt.root.right.left = Node(6);    
+bt.root.right.right = Node(7);    
+
+#Converts the given binary tree to doubly linked list    
+bt.convertbtToDLL(bt.root);    
+
+#Displays the nodes present in the list    
+bt.display();