GreedyFlorist.cs

// Greedy Florist
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Solution {

    // Complete the getMinimumCost function below.
    static int getMinimumCost(int k, int[] c) {
        Array.Sort(c);
        var mainLoopCount = c.Length / k + 1;
        var result = 0;

        for (var loop = 0; loop < mainLoopCount; loop++)
        {
            for (int index = 0; index < k; index++)
            {
                if (loop * k + index >= c.Length)
                    break;

                var currentOriginal = c[c.Length - (loop * k + index) - 1];
                result += currentOriginal * (loop + 1);
            }
        }

        return result;
    }

    static void Main(string[] args) {
        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        string[] nk = Console.ReadLine().Split(' ');

        int n = Convert.ToInt32(nk[0]);

        int k = Convert.ToInt32(nk[1]);

        int[] c = Array.ConvertAll(Console.ReadLine().Split(' '), cTemp => Convert.ToInt32(cTemp))
        ;
        int minimumCost = getMinimumCost(k, c);

        textWriter.WriteLine(minimumCost);

        textWriter.Flush();
        textWriter.Close();
    }
}