#include <stdlib.h>
#include <time.h>
#include <errno.h>
#define DEFAULT_SIZE //הגודל ברירת מחדל שאת רוצה
static size_t uniques_size=0;
static int* uniques_arr;
static bool uniques_initialized=false;

void initialize_uniques(size_t size,  int seed)
{
    if (unqiues_initialized)
        unique_arr=realloc(unique_arr, sizeof(int)*size);
    else uniques_arr=calloc(size, sizeof(int));
    if (uniques_arr==NULL)
    {
        errno=ENOMEM;
        unique_initialized=false; //in case of reinitialization
        return;
    }
    srand(seed);
    for (int i=0; i<size; i++)
         uniques_arr[i] = i;
    uniques_initialized=true;
}

void int_swap(int* a, int* b)
{
    int temp=*a;
    *a=*b;
    *b=temp;
}
int generate_unique()
{
    if (!unique_initialized||uniques_size==0)
        initialize_uniques(DEFAULT_SIZE, time(NULL)) ;
    swap(&uniques_arr[rand()%uniques_size-1], &uniques_arr[uniques_size-1]);
    uniques_size--;
    return uniques_arr[uniques_size] ;
}


int uniques_left()
{
    return uniques_size;
}