I think I'm done, happy for you to take a look!

src/FlightRoutesGraph.java

@@ -0,0 +1,107 @@
+import edu.greenriver.sdev333.MathSet;
+import edu.greenriver.sdev333.*;
+
+
+
+public class FlightRoutesGraph
+{
+    // two sets need to model a graph (network)
+    // 1. a set of vertices (points, nodes> -  airports
+    // 2. a set of edges (connections, lines, relationships) - route between airports
+
+    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<>();           //BST ok here b/c strings are comparable
+        edges = new HashSet<>();          // must use HashSet here b/c edges are not comparable
+    }
+
+
+    public void addNode(String city)
+    {
+        nodes.add(city);
+    }
+
+    public void addEdge(String city1, String city2)
+    {
+        Edge connection = new Edge(city1,city2);
+        edges.add(connection);
+    }
+
+    MathSet<String> getNeighbors(String city)
+    {
+        //create an empty set to hold the results
+        MathSet<String> neighbors = new BSTSet<>();
+
+        //  loop through the edges and check
+        // if the city is either in node1 or node2
+
+        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();
+
+        // add all the cities first (nodes)
+        g.addNode("JFK");
+        g.addNode("ORD");
+        g.addNode("ATL");
+        g.addNode("MCO");
+        g.addNode("DEN");
+
+        //add connections between cities (edges, routes)
+        g.addEdge("JFK","MCO");
+        g.addEdge("ATL","JFK");
+        g.addEdge("ATL","MCO");
+        g.addEdge("DEN","ORD");
+        g.addEdge("ORD","ATL");
+        //more to go if you want
+
+        // look for direct flgihts from JFK
+        MathSet<String> directJFK = g.getNeighbors("JFK");
+        MathSet<String> directFromATL = g.getNeighbors("ATL");
+        for (String key: directJFK.keys())
+        {
+            System.out.println(key);
+        }
+        System.out.println();
+        for (String key: directFromATL.keys())
+        {
+            System.out.println(key);
+        }
+
+
+    }
+
+
+}

src/Main.java

@@ -1,5 +1,82 @@
+import edu.greenriver.sdev333.*;
+
+
 public class Main {
     public static void main(String[] args) {
         System.out.println("Hello world!");
+        //write some code to test out your methods for your set
+        //Create 2 sets
+        // add items to each of the sets (some same, some different)
+
+        //Test
+        // set intersection
+        // set union
+        // set difference
+
+        MathSet<String> set1 = new HashSet<>();
+        set1.add("Ken");
+        set1.add("Tina");
+        set1.add("Tyler");
+
+        MathSet<String> set2 = new HashSet<>();
+        set2.add("Ken");
+        set2.add("Josh");
+        set2.add("Tina");
+
+        // union set 1 and set 2, save into result 1
+        MathSet<String> result1 = set1.union(set2);
+        //print out keys from result1
+        for(String key: result1.keys())
+        {
+            System.out.println(key);
+        }
+        System.out.println();
+        result1 = set1.intersection(set2);
+        //print out keys from result1
+        for(String key: result1.keys())
+        {
+            System.out.println(key);
+        }
+        System.out.println();
+        result1 = set1.difference(set2);
+        //print out keys from result1
+        for(String key: result1.keys())
+        {
+            System.out.println(key);
+        }
+
+
+        MathSet<String> set11 = new BSTSet<>();
+        set11.add("A");
+        set11.add("B");
+        set11.add("C");
+
+        MathSet<String> set22 = new BSTSet<>();
+        set22.add("C");
+        set22.add("D");
+        set22.add("E");
+        set22.add("F");
+
+        // union set 11 and set 22, save into result 11
+        MathSet<String> result11 = set11.union(set22);
+        //print out keys from result11
+        for(String key: result11.keys())
+        {
+            System.out.println(key);
+        }
+        System.out.println();
+        result11 = set11.intersection(set22);
+        //print out keys from result11
+        for(String key: result11.keys())
+        {
+            System.out.println(key);
+        }
+        System.out.println();
+        result11 = set11.difference(set22);
+        //print out keys from result11
+        for(String key: result11.keys())
+        {
+            System.out.println(key);
+        }
     }
 }