implement Dates,Passwords,Palindromes methods in BonusExercises

src/main/java/BonusExercises.java

@@ -13,49 +13,60 @@ public class BonusExercises {
         return matcher.matches();
     }
 
-    /*
-        This method should find and return the first date in a string.
-
-        Supported formats:
-        - American:   MM/DD/YYYY   (e.g., 12/09/2023)
-        - British:    DD/MM/YYYY   (e.g., 12/09/2023 — same pattern, context matters)
-        - ISO:        YYYY-MM-DD   (e.g., 2024-07-15)
-        - Slash variant: YYYY/MM/DD (e.g., 2025/01/01)
-
-        If no match for a date is found in the string, return null.
-    */
     public String findDate(String string) {
-        // todo
+        if (string == null) {return null;}
+        String regex = "\\b(\\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12][0-9]|3[01])|\\d{4}/(0[1-9]|1[0-2])/(0[1-9]|[12][0-9]|3[01])|(0[1-9]|[12][0-9]|3[01])/(0[1-9]|1[0-2])/\\d{4})\\b";
+        Pattern pattern = Pattern.compile(regex);
+        Matcher matcher = pattern.matcher(string);
+        if (matcher.find()) {
+            return matcher.group();
+        }
         return null;
     }
 
-    /*
-        given a string, implement the method to detect all valid passwords
-        then, it should return the count of them
 
-        a valid password has the following properties:
-        - at least 8 characters
-        - has to include at least one uppercase letter, and at least a lowercase
-        - at least one number and at least a special char "!@#$%^&*"
-        - has no white-space in it
-     */
     public int findValidPasswords(String string) {
-        // todo
-        return -1;
+        String regex = "^(?=.*[a-z])(?=.*[A-Z])(?=.*\\d)(?=.*[^A-Za-z0-9])\\S{8,}$";
+        Pattern pattern = Pattern.compile(regex);
+        Matcher matcher = pattern.matcher(string);
+        String[] passwords = string.split(" ");
+        int count = 0;
+        for (String pass: passwords){
+            if (pattern.matcher(pass).matches()){
+                count++;
+            }
+        }
+        return count;
     }
     
-    /*
-        you should return a list of *words* which are palindromic
-        by word we mean at least 3 letters with no whitespace in it
-
-        note: your implementation should be case-insensitive, e.g. Aba -> is palindrome
-     */
     public List<String> findPalindromes(String string) {
         List<String> list = new ArrayList<>();
-        // todo
+        String regex = "\\b[a-zA-Z]{3,}\\b";
+        Pattern pattern = Pattern.compile(regex);
+        Matcher matcher = pattern.matcher(string);
+        while (matcher.find()) {
+            if (CheckPalindrome(matcher.group())) {
+                list.add(matcher.group());
+            }
+        }
         return list;
     }
 
+    private boolean CheckPalindrome(String str) {
+        str = str.toLowerCase();
+        int i = 0;
+        int j = str.length() - 1;
+        while (i < str.length() / 2 ) {
+            if (str.charAt(i) != str.charAt(j)) {
+                return false;
+            }
+            i++;
+            j--;
+
+        }
+        return true;
+    }
+
     public static void main(String[] args) {
         // you can test your code here
     }