SCHOOL OF CODE BUILDERS: Remove duplicates from a unsorted linked list

Remove duplicates from a unsorted linked list

#include <stdio.h>
#include <stdlib.h>
#define MAX 1000000

struct node
{
 int data;
 struct node *next;
};

struct node* newnode(int data)
{
 struct node *new=(struct node*)malloc(sizeof(struct node));
 new->data=data;
 new->next=NULL;
 return new;
}

void insertashead(struct node **head,int data)
{
 struct node *temp=newnode(data);
 if((*head)==NULL)
  *head=temp;
 else
 {
  temp->next=(*head);
  (*head)=temp;
 }
}

void printlist(struct node *head)
{
 while(head!=NULL)
 {
  printf("%d ",head->data);
  head=head->next;
 }
}

void deletenode(struct node *del)
{
 struct node *temp=del->next;
 del->data=temp->data;
 del->next=temp->next;
 free(temp);
}

void removeduplicates(struct node *head)
{
 struct node *current=head;
 int hash[MAX];
 memset(hash,0,sizeof(hash));
 while(current!=NULL)
 {
  if(hash[current->data]==1)
  {
   deletenode(current);
  }
  else
  {
   hash[current->data]=1;
   current=current->next;
  }
 }
}

int main(void) {
 struct node *head=NULL;
 int n,x,i,key;
 scanf("%d",&n);
 for(i=0;i<n;i++)
 {
  scanf("%d",&x);
  insertashead(&head,x);
 }
 printlist(head);
 printf("\n");
 removeduplicates(head);
 printlist(head);
 return 0;
}

Pages

Remove duplicates from a unsorted linked list