HackerRank: Tag Content Extractor

In a tag-based language like XML or HTML, contents are enclosed between a start tag and an end tag like <tag>contents</tag>. Note that the corresponding end tag starts with a /.

Given a string of text in a tag-based language, parse this text and retrieve the contents enclosed within sequences of well-organized tags meeting the following criterion:

1. The name of the start and end tags must be same. The HTML code <h1>Hello World</h2> is not valid, because the text starts with an h1 tag and ends with a non-matching h2 tag.

2. Tags can be nested, but content between nested tags is considered not valid. For example, in <h1><a>contents</a>invalid</h1>, contents is valid but invalid is not valid.

3. Tags can consist of any printable characters.

Sample Input

4

<h1>Nayeem loves counseling</h1>

<h1><h1>Sanjay has no watch</h1></h1><par>So wait for a while</par>

<Amee>safat codes like a ninja</amee>

<SA premium>Imtiaz has a secret crush</SA premium>

Sample Output

Nayeem loves counseling

Sanjay has no watch

So wait for a while

None

Imtiaz has a secret crush

Java Code:

import java.util.*;

import java.util.regex.*;

public class tagContentExtractor

{

    public static void main(String[] args){

       

        Scanner in = new Scanner(System.in);

        int testCases = Integer.parseInt(in.nextLine());

        while(testCases>0){

            String line = in.nextLine();

           

            Pattern p = Pattern.compile("<(.+)>([^<]+)<(/\\1)>");

            Matcher m = p.matcher(line);

            boolean nf = false;

            while(m.find())

            {

                System.out.println(m.group(2));

                nf=true;

            }

            if(!nf)

                System.out.println("None");

           

            testCases--;

        }

        in.close();

    }

}