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  1. Prepare
  2. Java
  3. Strings
  4. Tag Content Extractor
  5. Discussions

Tag Content Extractor

  • RodneyShag
     + 62 comments

    Java solution - passes 100% of test cases

    From my HackerRank solutions.

    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");
            }
        }
    }
}

    Let me try to explain the regular expression:

    <(.+)>

    matches HTML start tags. The parentheses save the contents inside the brackets into Group #1.

    ([^<]+)

    matches all the text in between the HTML start and end tags. We place a special restriction on the text in that it can't have the "<" symbol. The characters inside the parenthesis are saved into Group #2.

    </\\1>

    is to match the HTML end brace that corresponds to our previous start brace. The \1 is here to match all text from Group #1.