#include <stdio.h>
#include <stdlib.h>

#include <malloc.h>
#include <time.h>

#define N 128
#define K 32

#define MAX 256
#define THREADS 4

#define res(cond) abs(result[cond].a) * abs(result[cond].b)

struct equation {
    int a;
    int b;
};

int *array;

struct equation *result;
int result_size=2;
int result_in=0;

void generate_array()
{
    srandom(time(NULL));
    int i;
    array = (int *)malloc(sizeof(int)*N);
    for (i=0;i<N;i++)
    {
        array[i] = rand() % MAX;
    }
}

void print(int *data)
{
    int i;
    for(i=0;i<N;i++)
    {
        printf("%i ", data[i]);
    }
    printf("\n");
}

struct equation make_equation(int a, int b)
{
    return *(struct equation[]){a,b};
}

int main(void)
{
    // loop index
    int i,j;
    // equation variables:
    int a,b;

    if (THREADS < 4)
    {
        fprintf(stderr, "Minimum threads are: 4. Your's: %i\n", THREADS);
        exit(1);
    }

    // allocation memory for result
    result = malloc(sizeof(struct equation)*result_size);

    generate_array();

    printf("K: %i\n\n", K);

    for(i=0;i<N;++i)
    {
        for(j=0;j<N;++j)
        {
            a = array[i];
            b = array[j];

            if (b-a == K)
            {
                if(result_in >= result_size)
                {
                    result = realloc(result, sizeof(struct equation)*result_size*2);
                    result_size*=2;
                }

                // after insert increase index
                result[result_in++] = make_equation(a,b);
            }
        }
    }


    int max = res(0);
    struct equation tmp;

    for (i=0;i<result_in;i++)
    {
        if (max < res(i))
        {
            max = res(i);
            tmp.a = result[i].a;
            tmp.b = result[i].b;
        }
    }
    printf("|%i|*|%i| = %i\n", tmp.a, tmp.b, max);
    return 0;
}