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Author: saarikabhasi

cracking-the-coding-interview-problems/linkedlist/remove-duplicate-elements.py

@@ -0,0 +1,197 @@
+"""
+Remove duplicate elements from linkedlist
+
+i/p:12->11->12->2->14->11->16->2->None
+o/p: 12->11->2->14->16
+
+"""
+
+
+class Node():
+    def __init__(self,data) -> None:
+        self.data = data
+        self.next = None
+        
+class simpleLL():
+    def __init__(self) -> None:
+        self.head =None
+        self.size = 0
+
+    def __is_list_empty(self):
+        """
+        while deleting we have to make sure that the list is empty. This function checks if the 
+        linked list is empty
+        """
+        return self.head == None
+
+    def insert_at_end(self,data):
+        """
+        function to insert a data at the end
+        """
+        newnode = Node(data)
+        if not self.__is_list_empty():
+            p = self.head
+            while p.next:
+                p = p.next
+            p.next = newnode
+        else:
+            self.head = newnode
+
+        self.size +=1
+        
+    def insert_at_begin(self,data):
+        """
+        function to insert a data at the begin
+        """
+        newnode = Node(data)
+        if not self.__is_list_empty():
+            newnode.next = self.head
+            self.head = newnode
+        else:
+            self.head = newnode
+        self.size +=1
+    
+    def insert_new_node_after_given_data(self,afterData,data):
+        """
+        function to insert a new node after the data
+        """
+        newnode = Node(data)
+        if not self.__is_list_empty():
+            p = self.head
+
+            while  p and p.data !=afterData :
+                p = p.next
+
+            if p == None:
+                print("cant find data")
+            else:
+                if p.next:
+                    after = p.next
+                    newnode.next = after
+
+                p.next = newnode
+        else:
+            print("List empty")
+            return
+        self.size +=1
+    
+    def delete_node(self,node):
+        """
+        Delete given node
+        
+        """
+        if node == self.head:
+            #delete head node
+            self.head = self.head.next
+        elif node.next ==None:
+            #last node
+            p =self.head
+            while p.next !=node:
+                p= p.next 
+            
+            #make last second node point to None
+            p.next = None
+        else:
+            #middle node
+            p =self.head
+            while p.next !=node:
+                p =p.next
+            p.next = node.next
+
+        self.size -=1
+
+    def show(self):
+        p = self.head
+        while p :
+            print(p.data)
+            p =p.next
+        print("====================")
+            
+class remove_dups():
+    def __init__(self,llobj) -> None:
+
+        self = llobj
+        
+
+
+    def remove_dups_with_hash(self,lobj):
+        """
+        Remove duplicate item in unsorted list using hash
+
+        Time: O(n)
+        Space: O(N)        
+        """
+        self = lobj
+        p = self.head 
+        hash = dict()
+        while p :
+            if  p.data not in hash.keys():
+                hash[p.data] = p.data
+            else:
+                self.delete_node(p)
+            p = p.next
+    
+    def remove_dups_with_two_pointers(self,lobj):
+        """
+        Remove duplicate item in unsorted list using two pointer
+        Time: O(n^2)
+        Space: O(1)
+
+        
+        """
+        self = lobj
+    
+        p1 = self.head
+        if p1 == None or p1.next == None :
+            return
+        p2 =p1.next
+
+        while p1.next != None and p2.next !=None:
+            if p1.data !=p2.data:
+                p2 =p2.next
+            else:
+                #delete p2
+                self.delete_node(p2)
+                p1 = p1.next
+                p2 = p1.next
+                
+        
+
+
+        
+
+    
+lobj = simpleLL()
+lobj.insert_at_end(12)
+lobj.insert_at_end(11)
+lobj.insert_at_end(12)
+lobj.insert_at_end(2)
+lobj.insert_at_end(11)
+lobj.insert_at_end(16)
+lobj.insert_at_end(2)
+lobj.insert_new_node_after_given_data(2,14)
+
+lobj.show()
+
+robj = remove_dups(lobj)
+robj.remove_dups_with_hash(lobj)
+lobj.show()
+
+robj.remove_dups_with_two_pointers(lobj)
+lobj.show()
+
+
+       
+            
+
+            
+
+
+
+            
+
+  
+            
+
+
+