import java.util.*;

/*
 * We need to get all of the keys. We only need to open doors if they prevent
 * us from getting to a key.
 * 
 * - Order the keys and their locations first in the tunnels?
 * - The order of keys is always a to z? Not necessarily.
 * - If we get to a door and we don't have the key to get through it then backtrack
 *   and find the key? Or don't even go there in the first place?
 * - If another key is closer to our current location than going through the
 *   next door then collect the key for shortest path.
 * - Go for all keys in sae direction until we hit a door that
 *   we can't pass then change direction.
 *
 * BFS from current location to next key.
 */

public class Explorer
{
    public Explorer (Map theMap, boolean debug)
    {
        _theMap = theMap;
        _start = _theMap.getEntrance();
        _totalNumnberOfKeys = _theMap.numberOfKeys();
        _states = new ArrayDeque<State>();
        _allStates = new Vector<State>();
        _debug = debug;
    }

   /*
    * Algorithm:
    *
    * - initial starting point @
    * - move to find next key
    * - if we hit a door ...
    *      if we have the key, keep going
    *      if we do not have the key, we can't get through the door so we
    *      need to stop going in that direction and find the key.
    * - each time we find a key, reset the starting point and remember
    *   to reset the visited bit in each Node.
    * - keep going until we hit a door or find all keys
    */

    public int findAllKeys ()
    {
        System.out.println("starting at "+_start);

        _states.offer(new State(_start, Collections.emptySet(), 0));

        while (_states.size() > 0)
        {
            System.out.println("states size "+_states.size());

            State theState = _states.pop();
            
            System.out.println("totalKeys "+_totalNumnberOfKeys);
            System.out.println("State keys "+theState.numberOfKeys());

            if (theState.numberOfKeys() == _totalNumnberOfKeys)
                return theState.numberOfSteps();

            for (Coordinate nextPosition : theState.getPosition().directions())
            {
                System.out.println("nextPosition "+nextPosition);

                if (_theMap.validPosition(nextPosition))
                {
                    System.out.println("valid");

                    char content = _theMap.getContent(nextPosition);

                    System.out.println("content "+content);

                    if (Util.isDoor(content) && !theState.hasKey(content))
                    {
                        System.out.println("Is a door and we don't have the key!");
                        continue;
                    }

                    System.out.println("here");

                    Set<Character> keys = theState.getKeys();

                    if (Util.isKey(content))
                    {
                        System.out.println("is key");

                        keys = new HashSet<Character>(keys);
                        keys.add(content);
                    }

                    State nextState = new State(nextPosition, keys, theState.numberOfSteps()+1);

                    System.out.println("nextState "+nextState);

                    if (!_allStates.contains(nextState))
                    {
                        _allStates.add(nextState);

                        System.out.println("there");

                        _states.add(nextState);

                        System.out.println("Adding state "+nextState);
                    }
                    else
                        System.out.println("already added");
                }
                else
                    System.out.println(nextPosition+" is invalid");
            }

            System.out.println("State sizes here "+ _states.size());
        }
        
        System.out.println("No route found!!");

        return -1;
    }

    private Map _theMap;
    private Coordinate _start;
    private int _totalNumnberOfKeys;
    private ArrayDeque<State> _states;
    private Vector<State> _allStates;
    private boolean _debug;
}
@@ -1512,32 +1512,56 @@
 llKeys ()%0A    %7B%0A
+        if (_debug)%0A    
         System.o
@@ -1572,25 +1572,25 @@
 rintln(%22
-s
+S
 tarting 
 at %22+_st
@@ -1581,16 +1581,23 @@
 tarting 
+search 
 at %22+_st
@@ -2597,32 +2597,72 @@
               %7B%0A
+                        if (_debug)%0A    
                 
@@ -2752,22 +2752,35 @@
     
+ %7D%0A
      
-continue;
+               else
 %0A   
@@ -2788,35 +2788,38 @@
                 
-%7D%0A%0A
+%7B%0A    
                 
@@ -2843,32 +2843,36 @@
 intln(%22here%22);%0A%0A
+    
                 
@@ -2930,32 +2930,36 @@
                 
+    
 if (Util.isKey(c
@@ -2979,34 +2979,42 @@
                 
+ 
-%7B%0A
+   %7B%0A    
                 
@@ -3048,24 +3048,28 @@
 %22is key%22);%0A%0A
+    
             
@@ -3137,24 +3137,28 @@
             
+    
 keys.add(con
@@ -3176,35 +3176,42 @@
                 
-%7D%0A%0A
+    %7D%0A%0A   
                 
@@ -3210,24 +3210,25 @@
             
+ 
 State nextSt
@@ -3305,32 +3305,36 @@
                 
+    
 System.out.print
@@ -3378,24 +3378,28 @@
             
+ 
+   
 if (!_allSta
@@ -3435,34 +3435,42 @@
                 
+  
-%7B%0A
+  %7B%0A    
                 
@@ -3497,32 +3497,36 @@
 dd(nextState);%0A%0A
+    
                 
@@ -3579,32 +3579,36 @@
                 
+    
 _states.add(next
@@ -3608,32 +3608,36 @@
 dd(nextState);%0A%0A
+    
                 
@@ -3703,34 +3703,42 @@
                 
+   
+ 
 %7D%0A
+    
                 
@@ -3738,32 +3738,36 @@
            else%0A
+    
                 
@@ -3807,24 +3807,46 @@
 dy added%22);%0A
+                    %7D%0A
             

Update Explorer.java