HR자바 Java Instanceof keyword

개요

HR자바 Java Instanceof keyword

• https://www.hackerrank.com/challenges/java-instanceof-keyword/problem
• 참고: 자바 instanceof

해커랭크 Java

#	문제	비고
HR자바 Object Oriented Programming e
43	HR자바 Java Inheritance I
44	HR자바 Java Inheritance II
45	HR자바 Java Abstract Class
46	HR자바 Java Interface
47	HR자바 Java Method Overriding
48	HR자바 Java Method Overriding 2 (Super Keyword)
49	HR자바 Java Instanceof keyword
50	HR자바 Java Iterator

---

import java.util.*;

class Student{}
class Rockstar{}
class Hacker{}

public class InstanceOFTutorial{
   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);
         if(element instanceof Student)
            a++;
         if(element instanceof Rockstar)
            b++;
         if(element instanceof Hacker)
            c++;
      }
      String ret = Integer.toString(a)+" "+ Integer.toString(b)+" "+ Integer.toString(c);
      return ret;
   }

   public static void main(String []args){
      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));
   }
}