private FiniteAutomata AddInitialState(FiniteAutomata NFA, FiniteAutomata DFA)
{
_ = DFA.AddState(NFA.InitialState());
IEnumerable <Transition> transitions = NFA.transitions.Where(x => x.fromState == NFA.InitialState());
foreach (var transition in transitions)
{
if (transition.toState.Count() == 1)
{
var toState = transition.toState.First();
_ = DFA.AddState(toState);
_ = DFA.AddTransition(transition);
}
else if (transition.toState.Count() > 1)
{
IEnumerable <State> toStates = transition.toState;
string newStateName = string.Join(STATE_SEPARATOR, toStates);
bool isFinalState = toStates.Any(state => state.FinalState == true);
var aState = new State(newStateName, false, finalState: isFinalState);
_ = DFA.AddState(aState);
_ = DFA.AddTransition(transition.transitionSymbol, transition.fromState.StateName, aState.StateName);
}
}
return(DFA);
}
private FiniteAutomata Convert(FiniteAutomata NFA, FiniteAutomata DFA)
{
Queue <State> statesQueue = new Queue <State>();
IEnumerable <State> states = DFA.states.Where(x => !x.InitialState);
foreach (State state in states)
{
statesQueue.Enqueue(state);
}
do
{
var fromState = statesQueue.Dequeue();
foreach (char symbol in DFA.alphabet)
{
string[] subStateNames = fromState.StateName.Split(STATE_SEPARATOR);
List <string> newStateNames = new List <string>();
bool isFinalState = false;
foreach (string subStateName in subStateNames)
{
var subState = NFA.states.First(x => x.StateName == subStateName);
Transition subTransition = NFA.transitions.FirstOrDefault(x => x.fromState == subState && x.transitionSymbol == symbol);
IEnumerable <State> subToStates = subTransition.toState;
newStateNames.AddNotExists(subToStates.Select(x => x.StateName));
if (!isFinalState)
{
isFinalState = subToStates.Any(state => state.FinalState);
}
}
string newStateName = string.Join(STATE_SEPARATOR, newStateNames.OrderBy(x => x));
State targetState;
if (!DFA.states.Any(x => x.StateName == newStateName))
{
targetState = new State(newStateName, false, isFinalState);
_ = DFA.AddState(targetState);
statesQueue.Enqueue(targetState);
}
else
{
targetState = DFA.states.First(x => x.StateName == newStateName);
}
_ = DFA.AddTransition(symbol, fromState.StateName, targetState.StateName);
}
}while (statesQueue.Count > 0);
return(DFA);
}
public FiniteAutomata ConvertNfaToDfa(FiniteAutomata input)
{
if (input.type == AutomataType.DFA)
{
return(input);
}
FiniteAutomata DFA = new FiniteAutomata(AutomataType.DFA, input.alphabet.ToList());
AddInitialState(input, DFA);
DFA = Convert(input, DFA);
return(DFA);
}
