circular_linked_list.py

data_structures/linked_list/circular_linked_list.py

@@ -0,0 +1,79 @@
+from __future__ import print_function
+
+class Node: #create a node
+    def __init__(self,data):
+        self.data = data   #giving data
+        self.next = None   #giving next to None
+
+class Circular_Linked_List:
+    def __init__(self):
+        self.last = None    #Initializing last to None
+
+    def insert_beginning(self,data):
+        newNode = Node(data)   #create node
+        if self.last == None:   #If last is None, Make newNode last
+          self.last = newNode
+          self.last.next = self.last
+        else:
+            newNode.next = self.last.next   #set newnode's next as head
+            self.last.next = newNode
+
+    def insert_end(self,data):
+        newNode = Node(data) 
+        if self.last == None:
+            self.last = newNode
+            self.last.next = self.last
+        else:
+            newNode.next = self.last.next #set newnode's next as head
+            self.last.next = newNode    
+            self.last = newNode #set newnode as last node
+
+    def delete_beginning(self):
+        node = self.last.next
+        self.last.next = node.next  #set last's next to first node's next
+        return node.data
+
+    def delete_end(self):
+        temp = self.last.next
+        while temp.next is not self.last:   #Traversing the list
+            temp=temp.next
+        node = self.last
+        temp.next = self.last.next   #set second last node's next to last's next
+        self.last = temp
+        return node.data
+
+    def print_list(self):
+        print("The list is:")
+        temp = self.last.next   #Creating iterator
+        while temp is not self.last:    #Traversing the list
+            print(temp.data)
+            temp = temp.next
+        print(temp.data)    #print last node
+
+	#End Class
+
+def main():
+    LL = Circular_Linked_List()
+    print("Inserting at beginning: ")
+    a1 = input()
+    LL.insert_beginning(a1)
+    print("Inserting at beginning: ")
+    a2 = input()
+    LL.insert_beginning(a2)
+    LL.print_list()
+    print("Inserting at the end: ")
+    a1 = input()
+    LL.insert_end(a1)
+    print("Inserting at the end: ")
+    a2 = input()
+    LL.insert_end(a2)
+    LL.print_list()
+    print("Deleting from beginning")
+    print(LL.delete_beginning()," deleted")
+    LL.print_list()
+    print("Deleting from end")
+    print(LL.delete_end()," deleted")
+    LL.print_list()
+
+if __name__ == '__main__':
+    main()