Merge pull request careermonk#14 from narkarum/patch-1

Update GraphAdjacencyMatrix.java

Author: careermonk

src/chapter09graphs/GraphAdjacencyMatrix.java

@@ -1 +1,126 @@
+/*Copyright (c) Dec 21, 2014 CareerMonk Publications and others.
+ * E-Mail           	: info@careermonk.com 
+ * Creation Date    	: 2015-01-10 06:15:46 
+ * Last modification	: 2006-05-31 
+               by		: Narasimha Karumanchi 
+ * File Name			: CLLNode.java
+ * Book Title			: Data Structures And Algorithms Made In Java
+ * Warranty         	: This software is provided "as is" without any 
+ * 							warranty; without even the implied warranty of 
+ * 							merchantability or fitness for a particular purpose. 
+ * 
+ */
+
 package chapter09graphs;
+import java.util.Iterator;
+import java.util.Random;
+import java.util.NoSuchElementException;
+
+public class Graph {
+    private static final String NEWLINE = System.getProperty("line.separator");
+
+    private final int V;
+    private int E;
+    private boolean[][] adjMatrix;
+
+    // empty graph with V vertices
+    public Graph(int V) {
+        if (V < 0) throw new IllegalArgumentException("Too few vertices");
+        this.V = V;
+        this.E = 0;
+        this.adjMatrix = new boolean[V][V];
+    }
+
+    // random graph with V vertices and E edges
+    public Graph(int V, int E) {
+        this(V);
+        if (E > (long) V*(V-1)/2 + V) throw new IllegalArgumentException("Too many edges");
+        if (E < 0)                    throw new IllegalArgumentException("Too few edges");
+        Random random = new Random();
+
+        // can be inefficient
+        while (this.E != E) {
+            int u = random.nextInt(V);
+            int v = random.nextInt(V);
+            addEdge(u, v);
+        }
+    }
+
+    // number of vertices and edges
+    public int V() { return V; }
+    public int E() { return E; }
+
+    // add undirected edge u-v
+    public void addEdge(int u, int v) {
+        if (!adjMatrix[u][v]) E++;
+        adjMatrix[u][v] = true;
+        adjMatrix[v][u] = true;
+    }
+
+    // does the graph contain the edge u-v?
+    public boolean contains(int u, int v) {
+        return adjMatrix[u][v];
+    }
+
+    // return list of neighbors of u
+    public Iterable<Integer> adjMatrix(int u) {
+        return new AdjIterator(u);
+    }
+
+    // support iteration over graph vertices
+    private class AdjIterator implements Iterator<Integer>, Iterable<Integer> {
+        private int u;
+        private int v = 0;
+
+        AdjIterator(int u) {
+            this.u = u;
+        }
+
+        public Iterator<Integer> iterator() {
+            return this;
+        }
+
+        public boolean hasNext() {
+            while (v < V) {
+                if (adjMatrix[u][v]) return true;
+                v++;
+            }
+            return false;
+        }
+
+        public Integer next() {
+            if (!hasNext()) {
+                throw new NoSuchElementException();
+            }
+            return v++;
+        }
+
+        public void remove()  {
+            throw new UnsupportedOperationException();
+        }
+    }
+
+    // string representation of Graph - takes quadratic time
+    public String toString() {
+        StringBuilder s = new StringBuilder();
+        s.append("Undirected graph" + NEWLINE);
+        s.append("Vertices:"+ V + " and edges:" + E + NEWLINE);
+        for (int u = 0; u < V; u++) {
+            s.append(u + ": ");
+            for (int v = 0; v < V; v++) {
+                s.append(String.format("%7s", adjMatrix[v][u]) + " ");
+            }
+            s.append(NEWLINE);
+        }
+        return s.toString();
+    }
+
+    // test code
+    public static void main(String[] args) {
+        int V = 5;
+        int E = 7;
+        Graph G = new Graph(V, E);
+        System.out.println(G.toString());
+    }
+
+}