From 3f702ed231134d224ee5fd5525f627a8058909a1 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Fri, 13 Mar 2015 19:34:04 +0100
Subject: Solutions w6

---
 Week6/src/Solver.java | 44 +++++++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 13 deletions(-)

(limited to 'Week6/src/Solver.java')

diff --git a/Week6/src/Solver.java b/Week6/src/Solver.java
index 137646c..9b78f27 100644
--- a/Week6/src/Solver.java
+++ b/Week6/src/Solver.java
@@ -1,37 +1,55 @@
+import java.util.HashSet;
+import java.util.PriorityQueue;
 import java.util.Queue;
 
-
 /**
  * A class that implements a breadth-first search algorithm
  * for finding the Configurations for which the isSolution predicate holds
+ * 
  * @author Pieter Koopman, Sjaak Smetsers
- * @version 1.3
- * @date 28-02-2013
+ * @author Camil Staps, s4498062
  */
+@SuppressWarnings("Convert2Diamond")    // We disable these warnings for Java <=1.7 compatibility.
 public class Solver
 {
     // A queue for maintaining graphs that are not visited yet.
-    Queue<Configuration> toExamine;
+    private final Queue<Node<Configuration>> toExamine = new PriorityQueue<Node<Configuration>>();
+    private final HashSet<Configuration> examined = new HashSet<Configuration>();
+    
+    private Node winner = null;
 
     public Solver(Configuration g) {
-        throw new UnsupportedOperationException("Solver: not supported yet.");        
+        toExamine.add(new Node(null, g));
     }
     
     /* A skeleton implementation of the solver
      * @return a string representation of the solution
      */
-    public String solve () {
-        while (! toExamine.isEmpty() ) {
-            Configuration next = toExamine.remove();
-            if ( next.isSolution() ) {
-                return "Success!";
+    public boolean solve () {
+        while (!toExamine.isEmpty()) {
+            Node next = toExamine.remove();
+            Configuration nextConfiguration = (Configuration) next.getItem();
+            examined.add(nextConfiguration);
+            if (nextConfiguration.isSolution()) {
+                winner = next;
+                return true;
             } else {
-                for ( Configuration succ: next.successors() ) {
-                    toExamine.add  (succ);
+                for (Configuration succ: nextConfiguration.successors()) {
+                    if (!examined.contains(succ)) {
+                        toExamine.add(new Node(next, succ));
+                    }
                 }
             }
         }
-        return "Failure!";
+        return false;
+    }
+    
+    /**
+     * Return the winning Node (from which the path can be reconstructed)
+     * @return the node in which we found a solution
+     */
+    public Node getWinner() {
+        return winner;
     }
     
 }
-- 
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