Split a linked list into two equal size list - DS TUTORIAL

demonstrate how to splits the list into two equal size list having same data inside.

Description:

In this example it has mainly three function one for inserting data into list another for printing the list and last one for split of list. 

Code:

# include <stdio.h>
# include <stdlib.h>
struct node
{
int data;
struct node *link;
};

void splitlist(struct node *p, struct node **q, int n)
     {
      struct node *temp;
 int  i =1;
 temp = p;
 while( i < n)
 {
  temp  =  temp->link;
  i++;
 }
 *q = temp->link;
 temp->link  =  p;
 temp = *q;
  while(temp->link != p)
  temp = temp ->link;
  temp->link = *q;
 }


struct node *insertnode(struct node *p , int n)
{
struct node *temp;
 if(p==NULL)
 {
 p=(struct node *)malloc(sizeof(struct node));
  if(p==NULL)
  {
  printf("Error\n");
  exit(0);
  }
  p-> data = n;
  p-> link = p;
 }
  else
 {
 temp = p;
 while (temp-> link != p)
 temp = temp-> link;
 temp-> link =(struct node *)malloc(sizeof(struct node));
 if(temp -> link == NULL)
 {
  printf("Error\n");
  exit(0);
 }
 temp = temp-> link;
 temp-> data = n;
 temp-> link = p;
 }
 return (p);
}
void printlist ( struct node *p  )
{
struct node *temp;
temp = p;
printf("The data values in the list are\n");
  if(p!= NULL)
   do
   {
   printf("%d\t",temp->data);
   temp=temp->link;
   } while (temp!= p);

  else
   printf("empty list\n");
 }

void main()
{
 int n,num;
 int x;
 struct node *start1 = NULL ;
 struct node *start2=NULL;
 printf("Enter the number of node for each splited list \n");
 scanf("%d",&n);
 num = n;
 n*=2; /* this is done to have data multiple of two
  so that it split into two equal parts. */
 while ( n-- > 0 )
 {
 printf( "\nEnter data to be placed in node\n");
 scanf("%d",&x);
 start1 = insertnode ( start1 , x );
 }
 printlist ( start1 );
 splitlist(start1,&start2,num);
 printf("\nFirst list is:\n");
 printlist(start1);
 printf("\nSecond list is:\n");
 printlist(start2);

}

Output: