diff --git a/src/edu/caltech/cs2/coloring/NodeGraph.java b/src/edu/caltech/cs2/coloring/NodeGraph.java
index fd2fe1cc4c311ddd095785882629df73a0219677..7a0367fc61af088570c43d6af1490e906e577fc0 100644
--- a/src/edu/caltech/cs2/coloring/NodeGraph.java
+++ b/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("{");