HackerrankJava0024.java

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class HackerrankJava0024 {

	public static void main(String[] args) {
		// Java Regex 2 - Duplicate Words
		// https://www.hackerrank.com/challenges/duplicate-word/problem?isFullScreen=true

		String regex = "\\b(\\w+)(\\s+\\1\\b)+";
		Pattern p = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);

		Scanner in = new Scanner(System.in);
		int numSentences = Integer.parseInt(in.nextLine());

		while (numSentences-- > 0) {
			String input = in.nextLine();

			Matcher m = p.matcher(input);

			// Check for subsequences of input that match the compiled pattern
			while (m.find()) {
				input = input.replaceAll(m.group(0), m.group(1));
			}

			// Prints the modified sentence.
			System.out.println(input);
		}

		in.close();
	}

}