Java Iterator HackerRank Solution

Problem:-

Java Iterator class can help you to iterate through every element in a collection. Here is a simple example:

import java.util.*;
public class Example{

    public static void main(String []args){
        ArrayList mylist = new ArrayList();
        mylist.add("Hello");
        mylist.add("Java");
        mylist.add("4");
        Iterator it = mylist.iterator();
        while(it.hasNext()){
            Object element = it.next();
            System.out.println((String)element);
        }
    }
}

In this problem you need to complete a method func. The method takes an ArrayList as input. In that ArrayList there is one or more integer numbers, then there is a special string "###", after that there are one or more other strings. A sample ArrayListmay look like this:

element[0]=>42
element[1]=>10
element[2]=>"###"
element[3]=>"Hello"
element[4]=>"Java"

You have to modify the func method by editing at most 2 lines so that the code only prints the elements after the special string "###". For the sample above the output will be:

Hello
Java

Note: The stdin doesn't contain the string "###", it is added in the main method.

To restore the original code in the editor, click the top left icon on the editor and create a new buffer.

Solution:-

import java.util.*;

public class Main{

    

static Iterator func(ArrayList mylist){

Iterator it=mylist.iterator();

while(it.hasNext()){

Object element = it.next();

if(element instanceof String && ("###".equals((String)element)))

            break;

        }

return it;

}

@SuppressWarnings({ "unchecked" })

public static void main(String []args){

ArrayList mylist = new ArrayList();

Scanner sc = new Scanner(System.in);

int n = sc.nextInt();

int m = sc.nextInt();

for(int i = 0;i<n;i++){

mylist.add(sc.nextInt());

}

mylist.add("###");

for(int i=0;i<m;i++){

mylist.add(sc.next());

}

Iterator it=func(mylist);

while(it.hasNext()){

Object element = it.next();

System.out.println((String)element);

}

}

}