Tag Content Extractor :- HackerRank Java Solution

Problem:-

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.

Input Format

The first line of input contains a single integer,  (the number of lines). 
The  subsequent lines each contain a line of text.

Constraints

• Each line contains a maximum of  printable characters.
• The total number of characters in all test cases will not exceed .

Output Format

For each line, print the content enclosed within valid tags. 
If a line contains multiple instances of valid content, print out each instance of valid content on a new line; if no valid content is found, print None.

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

Solution:-

import java.util.Scanner;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/* Solution assumes we can't have the symbol "<" as text between tags */

public class Solution{

public static void main(String[] args){

Scanner scan = new Scanner(System.in);

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

while (testCases-- > 0) {

String line = scan.nextLine();

boolean matchFound = false;

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

Matcher m = r.matcher(line);

while (m.find()) {

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

matchFound = true;

}

if ( ! matchFound) {

System.out.println("None");

}

}

}

}