#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#include<string.h>
 
#define max 12
#define num 30
#define nam 24
 
typedef struct
{
	 char name[nam];
	 int score;
	 int rank;
}CONTESTANT;
 
typedef struct
{
	 CONTESTANT CA;
	 int next;
}HeapSpace;
 
typedef struct
{
	 HeapSpace *H;
	 int first;
}VirtualHeap, *VHeap;
 
typedef struct
{
	 int storage[max];
	 int ladder[max];
	 int nextrung;
}DualDataStruc, *DDS;
 
void initialize(DDS *D, VHeap *VH);
int myMalloc(VHeap *VH);
void myFree(VHeap *VH, int x);
int hash(char n[]);
void insert(DDS *D, VHeap *VH, int NOP);
void display(DDS D, VHeap VH);
 
void initialize(DDS *D, VHeap *VH)
{
	 int ctr;
 
	 *D = (DDS) malloc(sizeof(DualDataStruc));
	 *VH = (VHeap) malloc(sizeof(VirtualHeap));
	 (*VH)->H = (HeapSpace *) malloc(sizeof(HeapSpace) * num);
	 (*VH)->first = 0;
 
	 for(ctr = 0; ctr < num - 1; ctr++)
	 {
		  (*VH)->H[ctr].next = ctr + 1;
	 }
	 (*VH)->H[ctr].next = -1;
 
	 for(ctr = 0; ctr < max; ctr++)
		  (*D)->storage[ctr] = -1;
 
	 (*D)->nextrung = 0;
}
 
int myMalloc(VHeap *VH)
{
	 int temp;
 
	 temp = (*VH)->first;
	 printf("%d\n", temp);
 
	 if(temp != -1)
	 {
		  (*VH)->first = (*VH)->H[temp].next;
 
		  printf("%d ", (*VH)->first);
	 }
 
	 return temp;
}
 
void myFree(VHeap *VH, int x)
{
	 int temp;
 
	 if(x != -1)
	 {
		  (*VH)->H[x].next = (*VH)->first;
		  (*VH)->first = x;
	 }
}
 
int hash(char n[])
{
	 int ctr, sum = 0;
 
	 for(ctr = 0; ctr < strlen(n); ctr++)
		  sum += (int)n;
 
	 return sum % max;
}
 
void insert(DDS *D, VHeap *VH, int NOP)
{
	 int ctr;
	 int x, h;
	 char n[nam];
 
	 printf("Enter the name of the contestant:\n");
	 for(ctr = 0; ctr < NOP; ctr++)
	 {
		  flushall();
		  gets(n);
 
		  x = myMalloc(&(*VH));
		  h = hash(n);
 
		  strcpy((*VH)->H[x].CA.name, n);
 
		  (*VH)->H[x].next = (*D)->storage[h];
		  (*D)->storage[h] = x;
		  (*D)->ladder[++((*D)->nextrung)] = x;
	 }
}
 
void display(DDS D, VHeap VH)
{
	 int ctr;
 
	 for(ctr = 1; ctr <= D->nextrung; ctr++)
		  puts(VH->H[D->ladder[ctr]].CA.name);
 
	 getch();
	 clrscr();
}
 
void main(void)
{
	 DDS D;
	 VHeap VH;
	 int NOP;
 
	 initialize(&D, &VH);
 
	 do
	 {
		  printf("How many players are there? ");
		  scanf("%d", &NOP);
 
		  if(NOP < 1 || NOP > 12)
		  {
				printf("You can only input 1 to 12 players");
				getch();
		  }
		  clrscr();
	 }while(NOP < 1 || NOP > 12);
 
	 insert(&D, &VH, NOP);
 
	 display(D, VH);
}