HackerrankJava0048.java

import java.util.ArrayList;
import java.util.Scanner;

public class HackerrankJava0048 {

	public static void main(String[] args) {
		// Java Instanceof keyword
		// https://www.hackerrank.com/challenges/java-instanceof-keyword/problem?isFullScreen=true

		ArrayList mylist = new ArrayList();
		Scanner sc = new Scanner(System.in);
		int t = sc.nextInt();
		for (int i = 0; i < t; i++) {
			String s = sc.next();
			if (s.equals("Student"))
				mylist.add(new Student());
			if (s.equals("Rockstar"))
				mylist.add(new Rockstar());
			if (s.equals("Hacker"))
				mylist.add(new Hacker());
		}
		System.out.println(count(mylist));
	}

	static String count(ArrayList mylist) {
		int a = 0, b = 0, c = 0;
		for (int i = 0; i < mylist.size(); i++) {
			Object element = mylist.get(i);

			// --- You need to update this line ---
			if (element instanceof Student)
				a++;
			// --- You need to update this line ---
			if (element instanceof Rockstar)
				b++;
			// --- You need to update this line ---
			if (element instanceof Hacker)
				c++;
		}
		String ret = Integer.toString(a) + " " + Integer.toString(b) + " " + Integer.toString(c);
		return ret;
	}

}

class Student {
}

class Rockstar {
}

class Hacker {
}