distinctYears.java

// Find distinct years
/*
  Find all the distinct years present in the a given string.
*/

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

public class Main
{
    public static void main(String[] args) {
      final String string = "the date 10-12-1996 is ahead of 10-12-1995 but befor 10-12-2001";
      final String regex = "[0-9]{2}-[0-9]{2}-[0-9]{4}";

      final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE);
          final Matcher matcher = pattern.matcher(string);
          Set<String> years = new HashSet<String>(); 
          while (matcher.find()) {
              String date = matcher.group(0);
              String year = date.substring(6, date.length());
              years.add(year);
          }
          System.out.println(years); 
    }
}