Kolikot

import java.util.Scanner;

public class Datatahti_kolikot {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        //Read input, we should only ever get numbers, so no datatype checks here
        Scanner input = new Scanner(System.in);
        int amount = input.nextInt();

        //We use the trianlge number formula Tn = ..., and solve it for 'n'
        //Casting to int always rounds down to the closest whole number
        int piles = (int) (-1 + Math.sqrt(1 - 4 * (-amount * 2))) / 2;
        //Output the number of most amount of pile we can have
        System.out.println(piles);

        //Easiest? way to give example piles, is just go up from 1 until the sum would be larger
        //than the amount of coins given
        int sum = 0;
        for (int i = 1; i < piles; i++) {
            sum += i;
            System.out.print(i + " ");
        }
        //Finally we output the final number for out example,
        //which is whatever is left from the amount of coins - the sum we got from the loop above
        System.out.println(amount - sum);
        
        //I think there might be a bit more efficient way of doing this by using the triangle number
        //sum funvtion, but what i have works as is, so I won't waste time on it now
//        int n = (piles * (piles + 1)) / 2;
//        System.out.println("\n\n" + n);
    }
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 1

Verdict: ACCEPTED

Test 7

Group: 1

Verdict: ACCEPTED

Test 8

Group: 1

Verdict: ACCEPTED

Test 9

Group: 1

Verdict: ACCEPTED

Test 10

Group: 1

Verdict: ACCEPTED

Test 11

Group: 2

Verdict: ACCEPTED

Test 12

Group: 2

Verdict: ACCEPTED

Test 13

Group: 2

Verdict: ACCEPTED

Test 14

Group: 2

Verdict: ACCEPTED

Test 15

Group: 2

Verdict: ACCEPTED

Test 16

Group: 2

Verdict: ACCEPTED

Test 17

Group: 2

Verdict: ACCEPTED

Test 18

Group: 2

Verdict: ACCEPTED

Test 19

Group: 2

Verdict: ACCEPTED

Test 20

Group: 2

Verdict: ACCEPTED

Test 21

Group: 3

Verdict: ACCEPTED

Test 22

Group: 3

Verdict: ACCEPTED

Test 23

Group: 3

Verdict: ACCEPTED

Test 24

Group: 3

Verdict: ACCEPTED

Test 25

Group: 3

Verdict: ACCEPTED

Test 26

Group: 3

Verdict: ACCEPTED

Test 27

Group: 3

Verdict: ACCEPTED

Test 28

Group: 3

Verdict: WRONG ANSWER

Test 29

Group: 3

Verdict: WRONG ANSWER

Test 30

Group: 3

Verdict: WRONG ANSWER