Input Format

The following input is handled for you the given stub code:

The first line contains an integer, , denoting the number of sentences.
Each of the  subsequent lines contains a single sentence consisting of English alphabetic letters and whitespace characters.


  • Each sentence consists of at most  English alphabetic letters and whitespaces.

Output Format

Stub code in the editor prints the sentence modified by the replaceAll line to stdout. The modified string must be a modified version of the initial sentence where all repeat occurrences of each word are removed.

hackerrank java regex 2 duplicate words solution

Java REgex 2 Duplicate words problem solution | HackerRank

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

public class DuplicateWords {

    public static void main(String[] args) {

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

        Scanner in = new Scanner(;
        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(,;
            // Prints the modified sentence.