public NDFA(U epsilon, NDFA <T, U> ndfa1, NDFA <T, U> ndfa2)
{
Epsilon = epsilon;
if (ndfa1 != null)
{
Alphabet.UnionWith(ndfa1.Alphabet);
}
if (ndfa2 != null)
{
Alphabet.UnionWith(ndfa2.Alphabet);
}
Transitions
= ndfa1 != null && ndfa2 != null
? ndfa1.Transitions.Concat(ndfa2.Transitions).ToDictionary(kvp => kvp.Key, kvp => kvp.Value)
: ndfa1 != null
? ndfa1.Transitions
: ndfa2 != null
? ndfa2.Transitions
: Transitions;
}
public bool addTransition(U input, T fromState, T toState)
{
// Check if state and input already exists
if (!Transitions.ContainsKey(fromState))
{
// Add the transition to the automaton
Transitions.Add(fromState, new Dictionary <U, T>());
}
// Check if input already exists
if (Transitions[fromState].ContainsKey(input))
{
// if it already exists we don't need to add it, so the method returns false
return(false);
}
// Add input to alphabet so the alphabet can dynamically be changed
Alphabet.Add(input);
Transitions[fromState].Add(input, toState);
States.Add(fromState);
States.Add(toState);
return(true);
}
public bool accept(U[] input)
{
if (!isValid())
{
throw new AutomatonInvalidException();
}
var currStates = StartStates;
foreach (U u in input)
{
if (!Alphabet.Contains(u))
{
throw new System.ArgumentException($"{u} is not part of alphabet");
}
HashSet <T> newStates = new HashSet <T>();
foreach (T state in currStates)
{
if (!Transitions.ContainsKey(state))
{
continue;
}
if (Transitions[state].ContainsKey(Epsilon))
{
newStates.UnionWith(Transitions[state][Epsilon]);
}
if (Transitions[state].ContainsKey(u))
{
newStates.UnionWith(Transitions[state][u]);
}
}
currStates = newStates;
}
return(EndStates.Intersect(currStates).Count() > 0);
}