HackerRank-Solutions/Java/Strings/Java Regex 3 - Username Checker/Solution.java

//     Author: Rodney Shaghoulian
//     Github: github.com/RodneyShag
// HackerRank: hackerrank.com/RodneyShag

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
   public static void main(String[] args) {
      Scanner in = new Scanner(System.in);
      int testCases = Integer.parseInt(in.nextLine());
      while (testCases > 0) {
         String username = in.nextLine();
         String pattern = "^[a-zA-Z]\\w{7,29}$";

         Pattern r = Pattern.compile(pattern);
         Matcher m = r.matcher(username);
          
         if (m.find()) {
            System.out.println("Valid");
         } else {
            System.out.println("Invalid");
         }
         testCases--;
      }
   }
}