Doing Bonus exercises

src/main/java/BonusExercises.java

@@ -19,8 +19,11 @@ public class BonusExercises {
             - Can't have underscores
             - Each segment (between dots) must follow same hyphen rules
      */
-    public boolean validateEmail(String email) {
-        String regex = ""; // todo
+    public boolean validateEmail(String email)
+    {
+        if(email == null) return false;
+
+        String regex = "^(?!.*\\.\\.)(?!.*@.*@)[^@.\\s][^@\\s]*@([a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?\\.)*[a-zA-Z0-9]([a-zA-Z0-9-]*[a-zA-Z0-9])?$";
         Pattern pattern = Pattern.compile(regex);
         Matcher matcher = pattern.matcher(email);
 
@@ -38,8 +41,31 @@ public class BonusExercises {
 
         If no match for a date is found in the string, return null.
     */
-    public String findDate(String string) {
-        // todo
+    public String findDate(String string)
+    {
+        if(string.isEmpty()) return null;
+
+        String isoPattern = "\\d{4}-\\d{2}-\\d{2}";
+        Pattern isoP = Pattern.compile(isoPattern);
+        Matcher isoMatcher = isoP.matcher(string);
+        if(isoMatcher.find()) return isoMatcher.group();
+
+        String slashVariantPattern = "\\d{4}/\\d{2}/\\d{2}";
+        Pattern slashP = Pattern.compile(slashVariantPattern);
+        Matcher slashMatcher = slashP.matcher(string);
+        if(slashMatcher.find()) return slashMatcher.group();
+
+
+        String usPattern = "(0[1-9]|1[0-2])/(0[1-9]|[12][0-9]|3[01])/\\d{4}";
+        Pattern usP =Pattern.compile(usPattern);
+        Matcher usMatcher = usP.matcher(string);
+        if(usMatcher.find()) return usMatcher.group();
+
+        String ukPattern = "(0[1-9]|[12][0-9]|3[01])/(0[1-9]|1[0-2])/\\d{4}";
+        Pattern ukP =Pattern.compile(ukPattern);
+        Matcher ukMatcher = ukP.matcher(string);
+        if(ukMatcher.find()) return ukMatcher.group();
+
         return null;
     }
 
@@ -53,9 +79,40 @@ public class BonusExercises {
         - at least one number and at least a special char "!@#$%^&*"
         - has no white-space in it
      */
-    public int findValidPasswords(String string) {
-        // todo
-        return -1;
+    public int findValidPasswords(String string)
+    {
+        if(string.isEmpty()) return 0;
+
+        String[] words = string.split(" ");
+        int count = 0;
+
+        for(String word : words)
+        {
+            if(word.length() < 8) continue;
+
+            boolean hasUpper = false;
+            boolean hasLower = false;
+            boolean hasSpecialChar = false;
+            boolean hasNumber = false;
+
+            for(int i = 0; i < word.length(); i++)
+            {
+                char x = word.charAt(i);
+                if (x >= 'A' && x <= 'Z') hasUpper = true;
+                if (x >= 'a' && x <= 'z') hasLower = true;
+                if (x >= '0' && x <= '9') hasNumber = true;
+            }
+            if(word.toString().contains("!") || word.toString().contains("@")
+                    || word.toString().contains("#") || word.toString().contains("$")
+                    || word.toString().contains("%") || word.toString().contains("*")
+                    || word.toString().contains("^") || word.toString().contains("&"))
+            {
+                hasSpecialChar = true;
+            }
+
+            if(hasUpper && hasLower && hasNumber && hasSpecialChar) count++;
+        }
+       return count;
     }
 
     /*
@@ -64,13 +121,41 @@ public class BonusExercises {
 
         note: your implementation should be case-insensitive, e.g. Aba -> is palindrome
      */
-    public List<String> findPalindromes(String string) {
+
+    public boolean isPalindrome(String n)
+    {
+        String a = n.toLowerCase();
+        boolean isEqual = true;
+        for(int i = 0; i < (a.length()) / 2; i++)
+        {
+            if(a.charAt(i) != a.charAt(n.length() - 1 - i))
+            {
+                isEqual = false;
+                break;
+            }
+        }
+        if(isEqual) return true;
+        return false;
+    }
+
+    public List<String> findPalindromes(String string)
+    {
         List<String> list = new ArrayList<>();
-        // todo
+
+        if(string.isEmpty()) return list;
+
+        String[] words = string.split(" ");
+        for(int i = 0; i < words.length; i++)
+        {
+            String newWord = words[i].replaceAll("[^a-zA-Z0-9]", "");
+            if(newWord.length() < 3) continue;
+            else if(isPalindrome(newWord) == true) list.add(newWord);
+        }
         return list;
     }
 
-    public static void main(String[] args) {
-        // you can test your code here
+    public static void main(String[] args)
+    {
+
     }
 }