Reorganizes NodeGraph

src/edu/caltech/cs2/coloring/NodeGraph.java

@@ -8,19 +8,29 @@ import edu.caltech.cs2.interfaces.ISet;
 
 public class NodeGraph {
 
+    private final Node[] nodes;
+
+    /**
+     * Represents one node in the graph
+     */
     private static class Node {
         public int name;
         public int color;
-        public ISet<Node> neighbors;
-        public ISet<Integer> neighborColors;
-        public ISet<Integer> neighborsColored;
+        public ISet<Node> neighbors; // The names of this node's neighbors
+        public ISet<Integer> neighborColors; // The colors which its neighbors use
+        public ISet<Integer> neighborsUncolored; // The names of its neighbors which aren't yet colored
 
         public Node(int name, int color) {
             this.name = name;
             this.color = color;
             this.neighbors = new ChainingHashSet<>();
             this.neighborColors = new ChainingHashSet<>();
-            this.neighborsColored = new ChainingHashSet<>();
+            this.neighborsUncolored = new ChainingHashSet<>();
+        }
+
+        public void addNeighbor(Node neighbor) {
+            this.neighbors.add(neighbor);
+            this.neighborsUncolored.add(neighbor.name);
         }
 
         @Override
@@ -41,8 +51,12 @@ public class NodeGraph {
             return this.name;
         }
     }
-    private final Node[] nodes;
 
+    /**
+     * Creates a new graph
+     * @param n The (fixed) number of vertices for the graph to have. They will be
+     *          "named" with the numbers 0 through n.
+     */
     public NodeGraph(int n) {
         this.nodes = new Node[n];
         for (int i = 0; i < n; i++) {
@@ -50,70 +64,101 @@ public class NodeGraph {
         }
     }
 
-    public int numberOfVertices() {
-        return this.nodes.length;
-    }
-
+    /**
+     * Whether or not a vertex is colored yet
+     * @param n The name of the vertex
+     * @return True if the vertex has a color, false if it doesn't yet
+     */
     public boolean isColored(int n) {
        return this.nodes[n].color != 0;
     }
 
+    /**
+     * Gets the color of a given vertex
+     * @param n The name of the vertex
+     * @return The vertex's color, or 0 if it doesn't have one yet
+     */
     public int getColor(int n) {
         return this.nodes[n].color;
     }
 
+    /**
+     * Sets the color of a vertex
+     * @param n The name of the vertex to set the color of
+     * @param color The color to set it to
+     */
     public void setColor(int n, int color) {
         if (this.isColored(n)) {
-            throw new IllegalArgumentException("" + n + " already has a color.");
+            throw new IllegalArgumentException(n + " already has a color.");
         }
         if (color <= 0) {
-            throw new IllegalArgumentException("only numbers >= 1 are valid colors");
+            throw new IllegalArgumentException("Only numbers >= 1 are valid colors, not " + color);
         }
         checkColoringIsValid(n, color);
         this.nodes[n].color = color;
         for (Node m : this.nodes[n].neighbors) {
             m.neighborColors.add(color);
-            m.neighborsColored.add(n);
+            m.neighborsUncolored.remove(n);
         }
     }
 
-    private void checkColoringIsValid(int n, int color) {
-        ISet<Integer> adjs = this.neighbors(n);
-        for (int v : adjs) {
-            if (this.nodes[v].color == color) {
-                throw new IllegalColoringException();
-            }
+    /**
+     * Gets a vertex's neighbors
+     * @param n The name of the vertex
+     * @return A list of the names of that vertex's neighbors
+     */
+    public ISet<Integer> neighbors(int n) {
+        ISet<Integer> adj = new ChainingHashSet<>();
+
+        ISet<Node> neighbors = this.nodes[n].neighbors;
+        for (Node neigh : neighbors) {
+            adj.add(neigh.name);
         }
 
+        return adj;
     }
 
-
-    public void addEdge(int n, int m) {
-        this.nodes[n].neighbors.add(this.nodes[m]);
-        this.nodes[m].neighbors.add(this.nodes[n]);
-    }
+    /**
+     * Gets the degree of saturation of a given vertex
+     * (ie: the number of unique colors across its neighbors)
+     * @param n The name of the vertex
+     * @return Its degree of saturation
+     */
     public int degreeOfSaturation(int n) {
         return this.nodes[n].neighborColors.size();
     }
 
-    public int numNeighbors(int n) {
-        return this.nodes[n].neighbors.size() - this.nodes[n].neighborsColored.size();
+    /**
+     * Gets the number of uncolored neighbors of a given vertex
+     * @param n The name of the vertex
+     * @return How many of its neighbors don't yet have colors
+     */
+    public int numUncoloredNeighbors(int n) {
+        return this.nodes[n].neighborsUncolored.size();
     }
+
+    /**
+     * Gets the (fixed) number of vertices in the graph
+     * @return The total number of vertices
+     */
     public int numVertices() {
         return this.nodes.length;
     }
 
-    public ISet<Integer> neighbors(int n) {
-        ISet<Integer> adj = new ChainingHashSet<>();
-
-        ISet<Node> neighbors = this.nodes[n].neighbors;
-        for (Node neigh : neighbors) {
-            adj.add(neigh.name);
-        }
-
-        return adj;
+    /**
+     * Adds an edge between two vertices
+     * @param n The name of one vertex
+     * @param m The name of the other vertex
+     */
+    public void addEdge(int n, int m) {
+        this.nodes[n].addNeighbor(this.nodes[m]);
+        this.nodes[m].addNeighbor(this.nodes[n]);
     }
 
+    /**
+     * Gets the current coloring of the graph
+     * @return A map between each vertex's name and its color
+     */
     public IDictionary<Integer, Integer> getColoring() {
         IDictionary<Integer, Integer> coloring = new ChainingHashDictionary<>(MoveToFrontDictionary::new);
         for (Node n : this.nodes) {
@@ -122,6 +167,22 @@ public class NodeGraph {
         return coloring;
     }
 
+    /**
+     * Checks if a vertex can validly be colored with a given color
+     * @param n The name of the vertex
+     * @param color The color for it to have
+     * @throws IllegalColoringException If this would cause an illegal coloring
+     */
+    private void checkColoringIsValid(int n, int color) {
+        ISet<Integer> adjs = this.neighbors(n);
+        for (int v : adjs) {
+            if (this.nodes[v].color == color) {
+                throw new IllegalColoringException();
+            }
+        }
+
+    }
+
     @Override
     public String toString() {
         StringBuilder result = new StringBuilder("{");