Solution.java

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.regex.*;

public class Solution {

  // Complete the getMinimumCost function below.
  static int getMinimumCost(int k, int[] c) {
    Arrays.sort(c);
    int cost = 0;
    int counter = 1;
    for (int i = c.length - 1; i >= 0; counter++) {
      for (int j = 0; j < k && i >= 0; j++, i--) {
        cost += c[i] * counter;
      }
    }

    return cost;

  }

  private static final Scanner scanner = new Scanner(System.in);

  public static void main(String[] args) throws IOException {
    BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

    String[] nk = scanner.nextLine().split(" ");

    int n = Integer.parseInt(nk[0]);

    int k = Integer.parseInt(nk[1]);

    int[] c = new int[n];

    String[] cItems = scanner.nextLine().split(" ");
    scanner.skip("(\r\n|[\n\r\u2028\u2029\u0085])?");

    for (int i = 0; i < n; i++) {
      int cItem = Integer.parseInt(cItems[i]);
      c[i] = cItem;
    }

    int minimumCost = getMinimumCost(k, c);

    bufferedWriter.write(String.valueOf(minimumCost));
    bufferedWriter.newLine();

    bufferedWriter.close();

    scanner.close();
  }
}