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

#define NUMBER_OF_FACTORS 3

int divisors(unsigned x, unsigned *list)
{
    unsigned i;
    unsigned count = 0;
    unsigned index = 0;
    unsigned limit;
    size_t size = 20;
    size_t incr = 20;
    size_t new_size;

    list = malloc(sizeof(unsigned) * size);
    if (list == NULL)
        return -1;

    limit = (unsigned)sqrt(x);

    for (i = 1; i <= limit; ++i) {
        if (x % i == 0) {
            if (index + 2 > size) {
                new_size = size + incr;
                list = realloc(list, sizeof(unsigned) * new_size);
                if (list == NULL) {
                    free(list);
                    list = NULL;
                    return -1;
                }
                size = new_size;
            }

            if (i == limit) {
                count += 1;
                list[index++] = i;
            }
            else {
                count += 2;
                list[index++] = i;
                list[index++] = x / i;
            }
                
        }
    }

    list = realloc(list, sizeof(unsigned) * index);
    if (list == NULL) {
        free(list);
        list = NULL;
        return -1;
    }

    return count;
}

int main(void)
{
    unsigned triangle = 0;
    int factors;
    unsigned i = 1;
    unsigned *divs;

    while (1) {
        triangle += i++;
        factors = divisors(triangle, divs);
        if (factors == -1) {
            fputs("No more RAM\n", stderr);
            exit(-1);
        }
        printf("%u\n", divs[0]);
        if (factors > NUMBER_OF_FACTORS)
            break;
        else
            free(divs);
    }

    printf("==> %u\n", triangle);
    for (i = 0; i < factors; ++i)
        printf("%u ", divs[i]);
    printf("\n");
    free(divs);

    return EXIT_SUCCESS;
}