Added 25 solutions

Java/Object Oriented Programming/Java Instanceof keyword/Solution.java

@@ -0,0 +1,42 @@
+//     Author: Rodney Shaghoulian
+//     Github: github.com/rshaghoulian
+// HackerRank: hackerrank.com/rshaghoulian
+
+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));
+   }
+}