# Remove Duplicate Nodes from Sorted Linked List

Remove Duplicate Nodes from Sorted Linked List” is again one of the foremost problem asked in many technical and algorithmic interviews of product-based company.

Here, we are given a sorted linked list and our task is to remove duplicates nodes from a sorted linked list.

```For example, we need to remove all the duplicated from the following list.
List:   45 -> 45 -> 46 -> 56 -> 67 -> 68 -> 68
After deleting duplicate nodes from a linked list, the linked list would be:
List: 45 -> 46 -> 56 -> 67 -> 68```

The steps required to remove duplicate nodes from a linked list is as follows:

1. Traverse the complete linked list.
2. While traversing, if the data of current node is equal to data of next node, point the pointer of current node to next of next and delete the next node of current node.

C++ Program to remove duplicate nodes from a Sorted Linked List is as follows:

```/* C++ Program to remove duplicate nodes from the sorted linked list */
#include<bits/stdc++.h>
using namespace std;

/* Structure of the node of the linked list */
typedef struct node
{
int data;
struct node *next;
}Node;

/* Function to Insert node at the end of the linked list */
void insert_end(Node **head, int ele)
{
/* Creating a new node */
Node *new_node;
new_node = (struct node*)malloc(sizeof(struct node));
new_node->data = ele;
new_node->next = NULL;

/* check whether the linked list is empty or not */

/* If Linked List is empty, then new node will become head of the linked list */
if(*head == NULL)
{
*head = new_node;
return;
}

/* If Linked List is not empty, then traverse the complete linked list and point the pointer
of last node of the linked list to the new node */
Node *temp = NULL;
temp = (*head);
while(temp->next != NULL)
temp=temp->next;
temp->next = new_node;
}
/* Function to remove duplicate nodes from the sorted linked list */
Node *removeDuplicates(Node *head)
{
/*
Traverse the complete linked list.While traversing, if the data of
current node is equal to data of next node, point the pointer of
current node to next of next and delete the next node of current node.
*/
Node *temp = head;
while(temp->next!=NULL)
{
if(temp->data == temp->next->data)
{
Node *p = temp->next;
temp-> next = p->next;
delete p;
}
else
{
temp = temp -> next;
}
}
return head;
}

/* Function to Print the Linked List  */
void print(Node *head)
{
Node *temp = head;
while(temp!=NULL)
{
cout<<temp->data<<" ";
temp=temp->next;
}
cout<<endl;
}
int main()
{
Node *head;
head = NULL;
/* Inserting Some Nodes in the Linked List in sorted manner */
insert_end(&head,45);
insert_end(&head,45);
insert_end(&head,46);
insert_end(&head,56);
insert_end(&head,67);
insert_end(&head,68);
insert_end(&head,68);
cout<<"Linked List Before Removing Duplicates:\n";
print(head);
cout<<"\nLinked List After Removing Duplicates:\n";
head = removeDuplicates(head);
print(head);
}
```
```OUTPUT:
Linked List Before Removing Duplicates:
45 45 46 56 67 68 68
Linked List After Removing Duplicates:
45 46 56 67 68```

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