Create ds_ll_O_on_24_04.py

This is ds_LL_own

Author: veerendra-poosala

ds_ll_O_on_24_04.py

@@ -0,0 +1,185 @@
+#creating linked list 
+from __future__ import print_function
+#creating class node
+class Node():
+    def __init__ (self,data=None,next=None):
+        self.data=data
+        self.next=next
+#creating class linked list 
+class linkedList():
+    def __init__(self,name="Unknown linked list",head=None):
+        self.head=head
+        self.name=name
+
+    #inserting elements
+    #inserting at beg:
+    def insert_at_beginning(self,new_data):
+        if self.head is None:
+            new_node=Node(new_data)
+            new_node.next=self.head
+            self.head=new_node
+            return
+        first_node=self.head
+        new_node=Node(new_data)
+        new_node.next=first_node
+        self.head=new_node
+    
+    #insert at end
+    def insert_at_end(self,new_data):
+        if self.head is None:
+            new_node=Node(new_data)
+            self.head=new_node
+            new_node.next=None
+            return
+        new_node=Node(new_data)
+        first_node=self.head
+        while first_node.next:
+            first_node=first_node.next
+        first_node.next=new_node
+        new_node.next=None
+
+    #insert at middle
+    def insert_at_middle(self,index,new_data):
+        if index<0 and index>self.get_length():
+            raise Exception("INVALID INDEX")
+            return
+        if self.head is None and index==0:
+            self.insert_at_beginning(new_data)
+            return
+        if index==0:
+            self.insert_at_beginning(new_data)
+            return
+        first_node=self.head
+        #new_node=Node(new_data)
+        count=0
+        while first_node.next:
+            if count==index-1:
+                new_node=Node(new_data)
+                new_node.next=first_node.next
+                first_node.next=new_node
+            first_node=first_node.next
+            count+=1
+    
+    #removing_an_element_at_beg
+    def removing_an_element_at_beg(self):
+        n=self.head
+        if self.head is None:
+            print("Removing from {} EMPTY LINKED LIST is not Possible".format(n))
+            return
+        first_node=self.head
+        self.head=self.head.next
+        first_node=None
+        return
+
+    
+    #removing_an_element_at_end
+    def removing_an_element_at_end(self):
+        n=self.head
+        length1=self.get_length()
+        if self.head is None:
+            print("Removing from {} EMPTY LINKED LIST is not Possible".format(n))
+            return
+        if length1 == 1:
+            self.removing_an_element_at_beg()
+            return
+        first_node=self.head
+        length2=length1-2
+        count=0
+        while first_node:
+            if count==length2:
+                first_node.next=first_node.next.next
+                return
+            first_node=first_node.next
+            count+=1
+
+        
+    #removing an element at middle
+    def removing_an_element_at_middle(self,index):
+        n=self.name
+        if index<0 and index>self.get_length():
+            raise Exception("INVALID INDEX")
+            return
+        if self.head is None:
+            print("Removing from {} EMPTY LINKED LIST is not Possible".format(n))
+            return
+        if index==0:
+            self.removing_an_element_at_beg()
+            return
+        first_node=self.head
+        count=0
+        while first_node:
+            if count==index-1:
+                first_node.next=first_node.next.next
+            first_node=first_node.next
+            count+=1
+            return
+
+    #finding length of ll
+    def get_length(self):
+        n=self.name
+        if self.head is None:
+            print("LENGTH OF THE {0} IS 0 ".format(n))
+            return
+        first_node=self.head
+        count=0
+        while first_node:
+            first_node=first_node.next
+            count+=1
+        #print("LENGTH OF THE {0} IS {1} ".format(n,count))
+        return count
+
+
+
+
+    #printing linkedlist
+    def print_ll(self):
+        n=self.name
+        if self.head is None:
+            print("{0} is EMPTY LINKED LIST".format(n) )
+            return
+        first_node=self.head
+        string=" "
+        while first_node:
+            string=str(first_node.data)+" ---> "
+            first_node=first_node.next
+            print(string,end=" ")
+        print()
+
+if __name__=="__main__":
+    l1=linkedList("linked list one")
+    l1.insert_at_beginning(25)
+    l1.insert_at_beginning(45)
+    l1.insert_at_beginning(65)
+    l1.insert_at_middle(0,75)
+    l1.insert_at_beginning(85)
+    l1.insert_at_middle(3,55)
+    l1.print_ll()
+    l1.removing_an_element_at_beg()
+    l1.print_ll()
+    l1.insert_at_beginning(85)
+    l1.print_ll()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.removing_an_element_at_end()
+    l1.print_ll()
+
+    l2=linkedList("linked list two")
+    l2.insert_at_end(1)
+    l2.insert_at_end(2)
+    l2.insert_at_end(3)
+    l2.insert_at_end(4)
+    l2.print_ll()
+    l2.removing_an_element_at_end()
+    l2.print_ll()
+    l2.removing_an_element_at_end()
+    l2.print_ll()
+    l2.removing_an_element_at_end()
+    l2.print_ll()
+    l2.removing_an_element_at_end()
+    l2.print_ll()
+