https://www.hackerrank.com/challenges/flowers

flowers.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>
#include <ctype.h>
#define MAX_LENGTH 100000
int fact(int num);
long long int mergedivide(long long int a[], long long int low, long long int high);
long long int mergeconquer(long long int a[], long long int low, long long int mid, long long int high);
long long int mergeconquer(long long int a[], long long int low, long long int mid, long long int high)
{
    long long int b[MAX_LENGTH];
    long long int i = low, j = mid + 1, k = 0;
    while (i <= mid && j <= high)
    {
        if (a[i] <= a[j])
            b[k++] = a[i++];
        else
            b[k++] = a[j++];
    }
    while (i <= mid)
        b[k++] = a[i++];
    while (j <= high)
        b[k++] = a[j++];
    k--;
    while (k >= 0) {
        a[low + k] = b[k];
        k--;
    }
    return 0;
} 
long long int mergedivide(long long int a[], long long int low, long long int high)
{
	long long int m;
    if (low < high) 
    {
        m = (high + low)/2;
        mergedivide(a, low, m);
        mergedivide(a, m + 1, high);
        mergeconquer(a, low, m, high);
    }
    return 0;
}
int fact(int num)
{
	int pint=num;
	while(--num)
		pint*=num;
	return pint;
}
int main()
{
	int i, k, n,fac,rem,j;
	long long int c[102],sum=0,pint,pont;
	scanf("%d%d", &n, &k);
	for(i=0; i<n; i++)
		scanf("%lld", &c[i]);
	fac=n/k;
	rem=n%k;
	mergedivide(c,0,n-1);
	i=0;
	pont=n-1;
	for (i = 0; i < fac; ++i)
	{
		pint=k;
		while(pint--)
		{
			c[pont]=(i+1)*c[pont];
			pont--;
		}
	}
	while(rem--)
	{
		c[rem]=(i+1)*c[rem];
	}
	for (i = 0; i < n; ++i)
	{
		sum+=c[i];
	}
	printf("%lld\n", sum);
   return 0;
}