Added 20 solutions

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

@@ -0,0 +1,31 @@
+//     Author: Rodney Shaghoulian
+//     Github: github.com/rshaghoulian
+// HackerRank: hackerrank.com/rshaghoulian
+
+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 = Complete this line in the editable area below  
+         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--;
+      }
+   }
+}

Java/Strings/Pattern Syntax Checker/Solution.java

@@ -1,7 +1,3 @@
-//     Author: Rodney Shaghoulian
-//     Github: github.com/rshaghoulian
-// HackerRank: hackerrank.com/rshaghoulian
-
 import java.util.Scanner;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
@@ -13,7 +9,7 @@ public class Solution {
     public static void main(String[] args){
         Scanner scan = new Scanner(System.in);
         int testCases = Integer.parseInt(scan.nextLine());
-        while (testCases > 0){
+        while (testCases-- > 0){
            String pattern = scan.nextLine();
            try {
                Pattern.compile(pattern);

Java/Strings/Tag Content Extractor/Solution.java

@@ -0,0 +1,31 @@
+//     Author: Rodney Shaghoulian
+//     Github: github.com/rshaghoulian
+// HackerRank: hackerrank.com/rshaghoulian
+
+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");
+            }
+        }
+    }
+}