diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/src/FlightRoutesGraph.java b/src/FlightRoutesGraph.java
new file mode 100644
index 0000000..8d89a0b
--- /dev/null
+++ b/src/FlightRoutesGraph.java
@@ -0,0 +1,74 @@
+import edu.greenriver.sdev333.BSTSet;
+import edu.greenriver.sdev333.MathSet;
+
+import java.util.HashSet;
+
+public class FlightRoutesGraph {
+
+
+
+    private class Edge {
+        private String node1;
+        private String node2;
+
+        public Edge(String from, String to) {
+            node1 = from;
+            node2 = to;
+        }
+    }
+
+    private MathSet<String> nodes;          
+
+    private MathSet<Edge> edges;            
+
+    public FlightRoutesGraph() {
+        nodes = new BSTSet<>();
+        edges = new HashSet<>();            
+    }
+
+    public void addNode(String city) {
+        nodes.add(city);
+    }
+
+    public void addEdge(String city1, String city2) {
+        Edge connection = new Edge(city1, city2);
+        edges.add(connection);
+    }
+
+
+
+    /**
+     *
+     * @param city
+     */
+    public MathSet<String> getNeighbors(String city) {
+        MathSet<String> neighbors = new BSTSet<>();
+
+        for (Edge e: edges.keys()) {
+            if (e.node1.equals(city)) {
+                neighbors.add(e.node2);
+            }
+            else if (e.node2.equals(city)) {
+                neighbors.add(e.node1);
+            }
+        }
+
+        return neighbors;
+    }
+
+    public static void main(String[] args) {
+        FlightRoutesGraph g = new FlightRoutesGraph();
+        g.addNode("JFK");
+        g.addNode("ORD");
+        g.addNode("ATL");
+        g.addNode("MCO");
+        g.addNode("DEN");
+        g.addEdge("ATL", "MCO");
+        g.addEdge("JFK", "MCO");
+        g.addEdge("DEN", "ORD");
+        g.addEdge("ORD", "ATL");
+        MathSet<String> directFromJFK = g.getNeighbors("JFK");
+        MathSet<String> directFromATL = g.getNeighbors("ATL");
+
+    }
+}
diff --git a/src/Main.java b/src/Main.java
index 3e59c38..5e464fe 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -1,5 +1,47 @@
+import edu.greenriver.sdev333.BSTSet;
+import edu.greenriver.sdev333.MathSet;
+import edu.greenriver.sdev333.SeparateChainingHashTable;
+import java.security.Key;
+
 public class Main {
     public static void main(String[] args) {
-        System.out.println("Hello world!");
+
+        String testChar = "P O O P I E";
+
+        MathSet<String> testset = new SeparateChainingHashTableSet<>();
+
+        Scanner input = new Scanner(testChar);
+
+        System.out.println(testset.isEmpty());
+
+        while(input.hasNext()){
+            String key = input.next();
+            testset.add(key);
+        }
+
+        System.out.println(testset.size());
+        System.out.println(testset.contains("P"));
+        System.out.println(testset.contains("O"));
+        System.out.println(testset.contains("O"));
+        System.out.println(testset.contains("P"));
+        System.out.println(testset.isEmpty());
+        System.out.println();
+
     }
+
+    MathSet<String> testset2 = new SeparateChainingHashTable<>();
+
+    testset2.add("P");
+    testset2.add("e");
+    testset2.add("e"); 
+    testset2.add("P"); 
+    testset2.add("I");
+    testset2.add("E"); 
+
+    System.out.println("testset.union(testset2): " + testset.union(testset2));
+    System.out.println("testset.intersection(testset2): " + testset.intersection(testset2));
+    System.out.println("testset.difference(testset2): " + testset.difference(testset2));
+
+
+
 }
\ No newline at end of file
diff --git a/src/edu/greenriver/sdev333/BSTSet.java b/src/edu/greenriver/sdev333/BSTSet.java
new file mode 100644
index 0000000..5204273
--- /dev/null
+++ b/src/edu/greenriver/sdev333/BSTSet.java
@@ -0,0 +1,160 @@
+package edu.greenriver.sdev333;
+
+import java.util.Iterator;
+
+public class BSTSet<KeyType> implements MathSet<KeyType> {
+    private class Node {
+        private KeyType key;
+        private Node left;
+        private Node right;
+        private int N;
+
+        public Node(KeyType key, int N) {
+            this.key = key;
+            this.N = N;
+        }
+    }
+
+    private Node root;
+
+    /**
+     * @param key key to be added into the set
+     */
+    @Override
+    public void add(Object key) {
+        root = add(root,key);
+
+    }
+
+    private Node add( Node current, KeyType key) {
+        if (current == null) {
+            return new Node(key, 1);
+        }
+
+        int x = key.compareTo(current.key);
+
+        if (x < 0) { 
+            current.left = add(current.left, key);
+        } else if (x > 0) {
+            current.right = add(current.right, key);
+        } else {
+            current.key = key;
+        }
+
+        current.N = size(current.left) + size(current.right) + 1;
+
+        return current;
+
+    }
+
+    /**
+     * @param key key to check
+     * @return true if key is in the set, false otherwise
+     */
+    @Override
+    public boolean contains(Object key) {
+        Node current = root;
+        while(current != null){
+            int x = key.compareTo(current.key);
+            if(x < 0){
+                current = current.left;
+            }else if(x > 0){
+                current = current.right;
+            }else {
+                return true;
+            }
+        }
+        return false;
+    }
+
+
+    /**
+     * @return true if the set is empty, false otherwise
+     */
+    @Override
+    public boolean isEmpty() {
+        return root == null || root.N == 0;
+    }
+
+    /**
+     * @return number of keys in the set.
+     */
+    @Override
+    public int size() {
+        return size(root);
+    }
+
+    private int size(Node current){
+        if(current == null){
+            return 0;
+        } else {
+            return size(current.left) + size(current.right) + 1;
+        }
+    }
+
+    /**
+     * @param other specified set to union
+     * @return the union of this set with other
+     */
+    @Override
+    public MathSet union(MathSet other) {
+        MathSet<KeyType> result = new BSTSet<KeyType>();
+
+        for(KeyType currentKey : this.keys()){
+                result.add(currentKey);
+        }
+
+        for (KeyType currentKey : other.keys()) {
+            if (!result.contains(currentKey)) {
+                result.add(currentKey);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * @param other specified set to intersect
+     * @return the intersection of this set with other
+     */
+    @Override
+    public MathSet intersection(MathSet other) {
+        MathSet<KeyType> result = new BSTSet<KeyType>();
+
+        for(KeyType currentKey : this.keys()){
+            if(other.contains(currentKey)) {
+                result.add(currentKey);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * @param other specified set to difference
+     * @return the difference of this set with other
+     */
+    @Override
+    public MathSet difference(MathSet other) {
+        MathSet<KeyType> result = new BSTSet<KeyType>();
+
+        Iterator<KeyType> itr = (Iterator<KeyType>) this.keys();
+
+        while (itr.hasNext()) {
+            KeyType currentKey = itr.next();
+            if (!other.contains(currentKey)) {
+                result.add(currentKey);
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * @return a collection of all keys in this set
+     */
+    @Override
+    public Iterable keys() {
+        Queue<KeyType> queue = new Queue<>();
+        inorder(root,queue);
+        return queue;
+    }
+}
\ No newline at end of file