Some

src/main/java/rocks/zipcode/io/quiz4/collections/ComparableTreeSet.java

@@ -1,18 +1,28 @@
 package rocks.zipcode.io.quiz4.collections;
 
+import java.util.Set;
+import java.util.TreeSet;
+
 /**
  * @author leon on 11/12/2018.
  */
 public class ComparableTreeSet<_> {
+
+
     public ComparableTreeSet(_... arr) {
 
+
     }
 
 
     public ComparableTreeSet() {
+
+        Set<_> set = new TreeSet<>();
     }
 
     public Integer compareTo(ComparableTreeSet<_> o) {
+
+
         return null;
     }
 }

src/main/java/rocks/zipcode/io/quiz4/collections/ZipCodeWilmington.java

@@ -2,22 +2,30 @@ package rocks.zipcode.io.quiz4.collections;
 
 import rocks.zipcode.io.quiz4.objectorientation.Student;
 
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.Map;
 
 /**
  * @author leon on 11/12/2018.
  */
 public class ZipCodeWilmington {
-    private Student student;
+    private ArrayList<Student> students;
     private double numberOfHours;
+    private Student student;
 
     public void enroll(Student student) {
-        this.student = student;
+        students.add(student);
     }
 
     public Boolean isEnrolled(Student student) {
 
-        return null;
+        if (students.contains(student)){
+            return true;
+        }
+
+
+        return false;
     }
 
     public void lecture(double numberOfHours) {
@@ -25,7 +33,28 @@ public class ZipCodeWilmington {
     }
 
     public Map<Student, Double> getStudyMap() {
+        Map<Student, Double> map = new HashMap<>();
+
 
         return null;
     }
+
+
+
+
+    public Student getStudent() {
+        return student;
+    }
+
+    public void setStudent(Student student) {
+        this.student = student;
+    }
+
+    public double getNumberOfHours() {
+        return numberOfHours;
+    }
+
+    public void setNumberOfHours(double numberOfHours) {
+        this.numberOfHours = numberOfHours;
+    }
 }

src/main/java/rocks/zipcode/io/quiz4/fundamentals/PalindromeEvaluator.java

@@ -4,18 +4,30 @@ package rocks.zipcode.io.quiz4.fundamentals;
 import com.sun.deploy.util.StringUtils;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 /**
  * @author leon on 18/12/2018.
  */
 public class PalindromeEvaluator {
     public static String[] getAllPalindromes(String string) {
-        char[] arr = string.toCharArray();
-        for (char c : arr){
-            System.out.println(c);
+        StringBuilder builder = new StringBuilder();
+        Set<String> set = new HashSet<>();
+        for (int i = 0; i < (string.length()/2) + 1; i++) {
+            if (string.charAt(string.length() - 1 - i) == string.charAt(i)){
+                builder.append(string.charAt(i) + ",");
+                builder.append(string.substring(i, string.length()-i) + ",");
+            }
+        }
+
+        String[] strSet = builder.toString().split(",");
+        for (String s : strSet){
+            set.add(s);
         }
-        return null;
+
+        return set.toArray(new String[0]);
     }
 
     public static Boolean isPalindrome(String string) {

src/main/java/rocks/zipcode/io/quiz4/fundamentals/StringEvaluator.java

@@ -1,13 +1,14 @@
 package rocks.zipcode.io.quiz4.fundamentals;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.*;
 
 /**
  * @author leon on 11/12/2018.
  */
 public class StringEvaluator {
     public static String[] getAllPrefixes(String string) {
+        Set<String> set = new HashSet<>();
+
 
         StringBuilder builder = new StringBuilder();
         int index = 0;
@@ -15,16 +16,36 @@ public class StringEvaluator {
 
             for (int i = 0; i < string.length(); i++) {
                 builder.append(string.charAt(i) + ",");
-                for (int j = 1; j < string.length()-1; j++) {
-                    builder.append(string.substring(i) + ",");
+                builder.append(string.substring(i) + ",");
+                if (i < string.length()/2) {
+                    builder.append(string.substring(i, string.length() - 1) + ",");
                 }
             }
+            String[] arr = builder.toString().split(",");
 
-        return builder.toString().split(",");
+            for (String s : arr){
+                set.add(s);
+            }
+
+        return set.toArray(new String[0]);
     }
 
     public static String[] getCommonPrefixes(String string1, String string2) {
-        return null;
+            String[] str1 = getAllPrefixes(string1);
+            String[] str2 = getAllPrefixes(string2);
+            StringBuilder builder = new StringBuilder();
+
+
+        for (int i = 0; i < str2.length; i++) {
+            if (Arrays.asList(str1).contains(str2[i])){
+                builder.append(str2[i] + ",");
+            }
+        }
+
+
+
+
+        return builder.toString().split(",");
     }
 
     public static String getLargestCommonPrefix(String string1, String string2) {

src/main/java/rocks/zipcode/io/quiz4/objectorientation/PalindromeObject.java

@@ -1,5 +1,7 @@
 package rocks.zipcode.io.quiz4.objectorientation;
 
+import com.sun.tools.javac.util.StringUtils;
+
 /**
  * @author leon on 18/12/2018.
  */

src/main/java/rocks/zipcode/io/quiz4/objectorientation/StringAssembler.java

@@ -4,10 +4,15 @@ package rocks.zipcode.io.quiz4.objectorientation;
  * @author leon on 11/12/2018.
  */
 public class StringAssembler {
+    private Character delimeter;
+    private String str;
+
     public StringAssembler(Character delimeter) {
+        this.delimeter = delimeter;
     }
 
     public StringAssembler append(String str) {
+        this.str = str;
         return null;
     }