public class Explorer
{
    public static final int MAXIMUM_KEYS = 26;

    public Explorer ()
    {
        _keys = new char[MAXIMUM_KEYS];
        _keysFound = 0;
    }

    @Override
    public String toString ()
    {
        if (_keysFound > 0)
        {
            String str = "Keys found: ";

            for (int i = 0; i < _keysFound; i++)
            {
                str += ", "+_keys[i];
            }

            return str;
        }
        else
            return "No keys found.";
    }

    private char[] _keys;
    private int _keysFound;
}
@@ -86,23 +86,72 @@
 plorer (
-)%0A    %7B
+Node start, boolean debug)%0A    %7B%0A        _start = start;
 %0A       
@@ -207,16 +207,40 @@
 nd = 0;%0A
+        _debug = debug;%0A
     %7D%0A%0A 
@@ -571,24 +571,49 @@
 d.%22;%0A    %7D%0A%0A
+    private Node _start;%0A
     private 
@@ -654,9 +654,37 @@
 sFound;%0A
+    private boolean _debug;%0A
 %7D

Update Explorer.java