static void Main(string[] args)
{
FSATransitionFunction transition = new FSATransitionFunction();
transition.Add(1, 'a', 3);
transition.Add(1, Symbols.Epsilon, 3);
transition.Add(2, 'a', 1, 2);
transition.Add(2, 'c', 3);
transition.Add(3, 'b', 1, 2);
FiniteStateAutomaton automaton = new FiniteStateAutomaton(
AutomatonHelper.CreateStates(3),
new HashSet <char>(new [] { 'a', 'b', 'c' }),
transition,
"1", AutomatonHelper.CreateFinalStates(3));
Console.WriteLine(automaton.IsWordInLanguage("ab"));
FiniteStateAutomaton dfa = (FiniteStateAutomaton)automaton.CreateDeterministicAutomaton();
Console.WriteLine(dfa.IsDeterministic(true));
Game1 game = new Game1();
game.Run();
}
public override Automaton <StateSymbolPair, HashSet <State> > CreateDeterministicAutomaton()
{
//return if we're already deterministic.
if (IsDeterministic())
{
return(new FiniteStateAutomaton(this));
}
FSATransitionFunction map = new FSATransitionFunction();
//ep-closure
HashSet <State> startStates = GetStatesAccessibleFrom(StartState, Symbols.Epsilon);
Stack <HashSet <State> > statesToVisit = new Stack <HashSet <State> >();
List <HashSet <State> > newStates = new List <HashSet <State> >();
statesToVisit.Push(startStates);
newStates.Add(startStates);
HashSet <State> finalStates = new HashSet <State>();
//consider the case our start state(s) are final
if (startStates.Intersect(FinalStates).Count() != 0)
{
Console.WriteLine("Start state(s) are final; adding..");
finalStates.Add(AutomatonHelper.CreateSetOfStates(startStates));
}
while (statesToVisit.Count > 0)
{
HashSet <State> stateSet = statesToVisit.Pop();
//consider each symbol in our alphabet; the transition from S => S is going to be the union of every possible accessible state
foreach (Symbol symbol in Alphabet)
{
//if the map contains this key, then we've already visited this state - don't do it again
if (!map.ContainsKey(new StateSymbolPair(AutomatonHelper.CreateSetOfStates(stateSet), symbol)))
{
HashSet <State> closure = new HashSet <State>();
foreach (State state in stateSet)
{
closure.UnionWith(GetStatesAccessibleFrom(state, symbol));
}
Console.WriteLine("From state {0}, on input {2}, the states are {1}", AutomatonHelper.CreateSetOfStates(stateSet),
AutomatonHelper.CreateSetOfStates(closure), symbol);
HashSet <State> stateToAdd = new HashSet <State>()
{
closure.Count == 0 ? AutomatonHelper.CreateSetOfStates(
Symbols.ErrorState.ToString()) : AutomatonHelper.CreateSetOfStates(closure)
};
//so now closure is every possible state reachable from some symbol. If it's empty, it's the error state
Console.WriteLine("Adding transition from state {0} on symbol {1}", AutomatonHelper.CreateSetOfStates(stateSet),
symbol);
map.Add(new StateSymbolPair(AutomatonHelper.CreateSetOfStates(stateSet), symbol), stateToAdd);
//keep a track of the sets we have
newStates.Add(stateToAdd);
//if we have a final state, the set of states is final
if (closure.Intersect(FinalStates).Count() != 0)
{
finalStates.Add(AutomatonHelper.CreateSetOfStates(closure));
}
//now we need to visit this set of states and find where it goes
if (closure.Count != 0)
{
statesToVisit.Push(closure);
}
}
}
}
HashSet <State> states = new HashSet <State>();
//the set of states is the unique keys in the mapping
foreach (var state in map.Keys.GroupBy(k => k.State))
{
states.Add(state.Key);
}
//the final states are any of the 'new' states which contain a final state
return(new FiniteStateAutomaton(states, Alphabet, map,
AutomatonHelper.CreateSetOfStates(startStates), finalStates));
}
public static void Add(this Dictionary <StateSymbolPair, HashSet <State> > dict, int startState, char input, params int[] moveTo)
{
dict.Add(new StateSymbolPair(startState.ToString(), input), AutomatonHelper.CreateFinalStates(moveTo));
}