private void completeBFS(final BFSNode node) {
   solved = true;
   shortestPath = node.getShortestPath();
   if (PuzzleConfiguration.isVerbose()) {
     System.out.println("done.");
   }
 }
 private void solveMultiThreaded(
     final long currentState, final int numOfThreads, final BitSet walls) {
   if (PuzzleConfiguration.isVerbose()) {
     System.err.print("Creating starting positons for " + numOfThreads + " threads...");
   }
   findStartingPositions(currentState, numOfThreads, walls);
   initialMovesEstimate = movesRequired = Node.h(currentState);
   if (PuzzleConfiguration.isVerbose()) {
     System.err.println("done");
   }
   if (!solved) {
     final int numElements = this.queue.size();
     this.workers = new DFSWorker[numElements];
     for (int i = numElements - 1; i >= 0; --i) {
       this.workers[i] = new DFSWorker(walls);
     }
     do {
       if (PuzzleConfiguration.isVerbose()) {
         System.out.print("\nSearching paths of depth " + movesRequired + "...");
       }
       final ExecutorService executor = Executors.newFixedThreadPool(numOfThreads);
       final Iterator<BFSNode> it = this.queue.iterator();
       int index = 0;
       while (it.hasNext()) {
         final BFSNode node = it.next();
         final String currentPath = node.getPath();
         final DFSWorker worker = this.workers[index++];
         worker.setConfig(node.boardConfig, currentPath, movesRequired, currentPath.length() - 1);
         executor.execute(worker);
       }
       executor.shutdown();
       try {
         executor.awaitTermination(Long.MAX_VALUE, TimeUnit.DAYS);
       } catch (final InterruptedException ie) {
         stop();
       }
       if (!solved) {
         movesRequired += 2;
       }
     } while (running);
   }
 }
 private void solveSingleThreaded(final long currentState, final BitSet walls) {
   initialMovesEstimate = movesRequired = Node.h(currentState);
   this.workers = new DFSWorker[1];
   final DFSWorker dfsWorker = new DFSWorker(walls);
   // Add to array so GUI can poll it for the stats in real time.
   this.workers[0] = dfsWorker;
   do {
     if (PuzzleConfiguration.isVerbose()) {
       System.out.print("\nSearching paths of depth " + movesRequired + "...");
     }
     dfsWorker.setConfig(currentState, "X", movesRequired, 0);
     dfsWorker.run();
     if (!solved) {
       movesRequired += 2;
     }
   } while (running);
 }