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

@@ -11,7 +11,7 @@ public class ComparableTreeSet<_> {
     public ComparableTreeSet() {
     }
 
-    public Integer compareTo(ComparableTreeSet<_> o) {
-        return null;
+    public int compareTo(ComparableTreeSet<_> o) {
+        return 0;
     }
 }

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

@@ -1,31 +1,56 @@
 package rocks.zipcode.io.quiz4.collections;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * @author leon on 11/12/2018.
  */
-public class SimpleStringGroup {
+public class SimpleStringGroup extends ArrayList{
+
+    List<String> list = new ArrayList();
+
+
     public SimpleStringGroup() {
-        throw new UnsupportedOperationException("Method not yet implemented");
+        List<String> list = new ArrayList();
+        this.list = list;
+
     }
 
     public Integer count() {
-        return null;
+        return list.size();
     }
 
     public void insert(String string) {
+        list.add(string);
     }
 
     public Boolean has(String valueToInsert) {
-        return null;
+        return list.contains(valueToInsert);
     }
 
     public String fetch(int indexOfValue) {
+
+        String[] strArray = list.toArray(new String[list.size()]);
+
+
+        for(int i =0; i <strArray.length; i++){
+            if(i == indexOfValue){
+                return strArray[i];
+            }
+        }
+
         return null;
     }
 
     public void delete(String valueToInsert) {
+
+        list.remove(valueToInsert);
+
     }
 
     public void clear() {
+
+        list.clear();
     }
 }

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

@@ -2,23 +2,53 @@ package rocks.zipcode.io.quiz4.collections;
 
 import rocks.zipcode.io.quiz4.objectorientation.Student;
 
-import java.util.Map;
+import java.util.*;
 
 /**
  * @author leon on 11/12/2018.
  */
-public class ZipCodeWilmington {
+public class ZipCodeWilmington extends ArrayList<Student> {
+
+    ArrayList<Student> zipCodeWilmington = new ArrayList<Student>();
+
+    Student student = new Student();
+
+    HashMap hashMap = new HashMap();
+
+
     public void enroll(Student student) {
+        zipCodeWilmington.add(student);
+
     }
 
     public Boolean isEnrolled(Student student) {
-        return null;
+
+        if(zipCodeWilmington.contains(student)){
+            return true;
+        }
+
+        return false;
     }
 
     public void lecture(double numberOfHours) {
+
+        for(Student s : zipCodeWilmington){
+            s.learn(numberOfHours);
+        }
+
     }
 
     public Map<Student, Double> getStudyMap() {
-        return null;
+
+
+        for(Student s : zipCodeWilmington){
+            hashMap.put(s,s.getTotalStudyTime().doubleValue());
+            System.out.println(s.getTotalStudyTime());
+
+        }
+
+
+
+        return hashMap;
     }
 }

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

@@ -1,18 +1,55 @@
 package rocks.zipcode.io.quiz4.fundamentals;
 
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * @author leon on 18/12/2018.
  */
 public class PalindromeEvaluator {
     public static String[] getAllPalindromes(String string) {
-        return null;
+
+        Set<CharSequence> stringSet = new HashSet<>();
+
+        for(int i =1; i <= string.length();i++){
+            for(int j =i; j<string.length(); j++){
+                if(isPalindrome(string.substring(i, j+1))){
+                    stringSet.add(string.substring(i,j+1));
+                }
+            }
+        }
+
+        stringSet.add(string);
+
+        return stringSet.toArray(new String[0]);
     }
 
     public static Boolean isPalindrome(String string) {
-        return null;
+
+        StringBuilder builder = new StringBuilder();
+        builder.append(string);
+
+        String reversedString = builder.reverse().toString();
+
+        for(int i = 0; i < string.length()/2; i++){
+            if(string.charAt(i) != string.charAt(string.length()-1-i)){
+                return false;
+            }else if(!reverseString(string).equals(reversedString)){
+                return false;
+            }
+        }
+
+        return true;
     }
 
     public static String reverseString(String string) {
-        return null;
+
+        StringBuilder builder = new StringBuilder();
+
+        builder.append(string);
+
+        builder = builder.reverse();
+
+        return builder.toString();
     }
 }

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

@@ -1,18 +1,68 @@
 package rocks.zipcode.io.quiz4.fundamentals;
 
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+
 /**
  * @author leon on 11/12/2018.
  */
 public class StringEvaluator {
     public static String[] getAllPrefixes(String string) {
-        return null;
+
+        HashSet<String> stringSet = new HashSet<>();
+
+        if(string.length() == 1){
+            Character letter = string.charAt(0);
+            stringSet.add(letter.toString());
+        }
+        else {
+
+            for(int i = 0; i < string.length(); i++){
+                for(int j = 1; j <= string.length()-i; j++){
+                    String sub = string.substring(i, i+j);
+                    stringSet.add(sub);
+                }
+            }
+        }
+
+        String[] strings = stringSet.toArray(new String[0]);
+        return strings;
     }
 
     public static String[] getCommonPrefixes(String string1, String string2) {
-        return null;
+
+        String[] string1Array = getAllPrefixes(string1);
+        String[] string2Array = getAllPrefixes(string2);
+
+        List<String> list = new ArrayList<>();
+
+        for(int i = 0; i < string1Array.length; i++){
+            for(int j = 0; j < string2Array.length; j++){
+                if(string1Array[i].equals(string2Array[j])){
+                        list.add(string1Array[i]);
+                }
+            }
+        }
+
+        return list.toArray(new String[0]);
     }
 
     public static String getLargestCommonPrefix(String string1, String string2) {
-        return null;
+
+        String[] commonPrefixes = getCommonPrefixes(string1,string2);
+
+        int index = 0;
+        int stringLength = commonPrefixes[0].length();
+
+
+        for(int i = 1; i <= commonPrefixes.length-1; i++){
+            if(commonPrefixes[i].length() > stringLength){
+                index = i;
+                stringLength = commonPrefixes[i].length();
+            }
+        }
+
+        return commonPrefixes[index];
     }
 }

src/main/java/rocks/zipcode/io/quiz4/generics/Group.java

@@ -1,28 +1,50 @@
 package rocks.zipcode.io.quiz4.generics;
 
+import java.util.ArrayList;
 import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
 
 /**
  * @author leon on 18/12/2018.
  */
-public class Group<_> {
+public class Group<_> extends LinkedList {
+
+    Group<_> group;
+
+
     public Group() {
+
+        group = new Group<_>();
+
+
         throw new UnsupportedOperationException("Method not yet implemented");
     }
 
     public Integer count() {
-        return null;
+        return group.size();
     }
 
     public void insert(_ value) {
+
+        group.add(value);
     }
 
     public Boolean has(_ value) {
-        return null;
+
+        if(group.contains(value)){
+            return true;
+        }
+
+        return false;
+
     }
 
     public _ fetch(int indexOfValue) {
-        return null;
+
+        _ test = (_) group.get(indexOfValue);
+
+        return test;
     }
 
     public void delete(_ value) {

src/main/java/rocks/zipcode/io/quiz4/generics/SortedGroup.java

@@ -6,13 +6,15 @@ package rocks.zipcode.io.quiz4.generics;
 public class SortedGroup<_> extends Group<_> {
     @Override
     public void insert(_ value) {
+        group.insert(value);
     }
 
     @Override
     public void delete(_ value) {
     }
 
-    public Integer indexOf(_ firstValue) {
-        return null;
+
+    public int indexOf(Object firstValue) {
+        return 0;
     }
 }

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

@@ -1,21 +1,34 @@
 package rocks.zipcode.io.quiz4.objectorientation;
 
+import rocks.zipcode.io.quiz4.fundamentals.PalindromeEvaluator;
+
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * @author leon on 18/12/2018.
  */
-public class PalindromeObject {
+public class PalindromeObject extends PalindromeEvaluator{
+
+    String input;
+
     public PalindromeObject(String input) {
+        this.input = input;
     }
 
     public String[] getAllPalindromes(){
-        return null;
+
+       return getAllPalindromes(input);
+
     }
 
     public Boolean isPalindrome(){
-        return null;
+
+
+        return isPalindrome(input);
     }
 
     public String reverseString(){
-        return null;
+        return reverseString(input);
     }
 }

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

@@ -1,17 +1,39 @@
 package rocks.zipcode.io.quiz4.objectorientation;
 
+import com.sun.deploy.util.StringUtils;
+import com.sun.tools.doclets.internal.toolkit.builders.AbstractBuilder;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.StringJoiner;
+
 /**
  * @author leon on 11/12/2018.
  */
 public class StringAssembler {
+
+
+    StringBuilder builder = new StringBuilder();
+
+    Character delimeter;
+
     public StringAssembler(Character delimeter) {
+        this.delimeter = delimeter;
     }
 
     public StringAssembler append(String str) {
-        return null;
+
+        builder.append(str);
+        builder.append(delimeter.toString());
+
+        return this;
     }
 
     public String assemble() {
-        return null;
+
+        builder.deleteCharAt(builder.toString().length()-1);
+
+
+        return builder.toString();
     }
 }

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

@@ -1,21 +1,28 @@
 package rocks.zipcode.io.quiz4.objectorientation;
 
+import rocks.zipcode.io.quiz4.fundamentals.StringEvaluator;
+
 /**
  * @author leon on 19/12/2018.
  */
-public class StringEvaluatorObject {
+public class StringEvaluatorObject extends StringEvaluator {
+
+    String string;
+
     public StringEvaluatorObject(String str) {
+        this.string = str;
     }
 
     public String[] getAllPrefixes() {
-        return null;
+
+        return getAllPrefixes(string);
     }
 
     public String[] getCommonPrefixes(String secondInput) {
-        return null;
+        return getCommonPrefixes(string,secondInput);
     }
 
     public String getLargestCommonPrefix(String secondInput) {
-        return null;
+        return getLargestCommonPrefix(string,secondInput);
     }
 }

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

@@ -4,17 +4,29 @@ package rocks.zipcode.io.quiz4.objectorientation;
  * @author leon on 11/12/2018.
  */
 public class Student {
+
+
+    Integer id;
+
+    Double totalStudyTime = 0.0;
+
+
+
     public Student() {
-        this(null);
     }
 
+
     public Student(Integer id) {
+        this.id = id;
     }
 
+
+
     public void learn(Double amountOfHours) {
+        totalStudyTime += amountOfHours;
     }
 
     public Double getTotalStudyTime() {
-        return null;
+        return totalStudyTime;
     }
 }