Best sum for coin change problem in C.

Best sum for coin change problem in C.

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <assert.h>
#define MAX_LEN 10
size_t count = 0, i = 0;

void appendToArray(int *array, int len, int value);
int cmp(const void *a, const void *b);
int *cache(int n);
int canSum(int target, int numbers[], int len, int *memo, int *array);
int main(int argc, char const *argv[])
{
    int *array = calloc(MAX_LEN, sizeof(int));

    assert(canSum(70, (int[]){10, 12, 5}, 3, cache(30), array));
    printf("Test 3: Passed\n");
    printf("[");
    while (array[i] != 0)
    {
        printf(" %d,", array[i]);
        i++;
    }
    printf("]\n");
    free(array);
    return 0;
}

int canSum(int target, int numbers[], int len, int *memo, int *array)
{

    qsort(numbers, len, sizeof(int), cmp);
    if (memo[target] == target)
    {
        return memo[target];
    }
    int remainder = -1;
    if (target == 0)
    {
        return true;
    }
    if (target < 0)
    {
        return false;
    }

    for (int i = 0; i < len; i++)
    {
        /**
         * *This is for debugging purpose.
         */

        // printf("Try [%d]:[%d - %d] = %d \n", i, target, numbers[i], target - numbers[i]);
        remainder = target - numbers[i];
        if (remainder == 0)
        {
            appendToArray(array, count, numbers[i]);
            return true;
        }
        if (canSum(remainder, numbers, len, memo, array) == true)
        {

            appendToArray(array, count, numbers[i]);
            memo[target] = true;
            return memo[target];
        }
    }
    memo[target] = false;
    return memo[target];
}

int *cache(int n)
{
    int *cache = (int *)malloc(sizeof(int) * n);
    for (int i = 0; i < n; i++)
    {
        cache[i] = -1;
    }
    return cache;
}

int cmp(const void *a, const void *b)
{
    const int *A = a, *B = b;
    /* a>b => -1, a<b => 1, a==b => 0 */
    return (*A < *B) - (*A > *B);
}

void appendToArray(int *array, int len, int value)
{
    array[len] = value;
    count += 1;
}