// 생성자
public EpsilonNFA(HashSet <string> _States, HashSet <string> _Inputs, Microsoft.Collections.Extensions.MultiValueDictionary <Tuple <string, string>, string> _TransitionFunctions, HashSet <string> _StartState, List <string> _FinalStates)
{
States = _States;
Inputs = _Inputs;
TransitionFunctions = _TransitionFunctions;
StartState = _StartState;
FinalStates = _FinalStates;
}
// 기본 생성자
public EpsilonNFA()
{
States = new HashSet <string>();
Inputs = DefaultInputs;
TransitionFunctions = new Microsoft.Collections.Extensions.MultiValueDictionary <Tuple <string, string>, string>();
StartState = new HashSet <string>();
FinalStates = new List <string>();
}
//e-NFA to DFA
public static DFA SubsetConstruction(EpsilonNFA epsilonNFA)
{
HashSet <string> startState = new HashSet <string>();
List <HashSet <string> > states = new List <HashSet <string> >();
Microsoft.Collections.Extensions.MultiValueDictionary <Tuple <string, string>, string> transitionFunctions = new Microsoft.Collections.Extensions.MultiValueDictionary <Tuple <string, string>, string>();
HashSet <string> reconstructedStates = new HashSet <string>();
List <string> finalStates = new List <string>();
foreach (var item in epsilonNFA.StartState)
{
startState.UnionWith(epsilonNFA.closure(item));
break;
}
foreach (var input in epsilonNFA.Inputs)
{
foreach (var state in startState)
{
foreach (var output in epsilonNFA.TransitionFunctions[new Tuple <string, string>(state, input)])
{
var newState = epsilonNFA.closure(output);
if (states.Contains(newState)) // 여기서 같은것이 반복되면 무시!
{
continue;
}
states.Add(newState);
string reconstructedStartState = "";
string reconstructedFinalState = "";
foreach (var item in startState)
{
reconstructedStartState += item;
}
foreach (var item in newState)
{
reconstructedFinalState += item;
}
if (reconstructedFinalState.Equals(string.Empty))
{
continue;
}
transitionFunctions.Add(new Tuple <string, string>(reconstructedStartState, input), reconstructedFinalState);
}
}
}
// 해쉬셋을 재구성해서 스테이트로 쓰기위해 하나의 문자열로 만든다
foreach (var set in states)
{
var newState = "";
foreach (var str in set)
{
newState += str;
}
reconstructedStates.Add(newState);
}
// 원래 NFA의 finalstate를 가진 것이 곧 DFA의 finalStte
foreach (var state in reconstructedStates)
{
foreach (var nfaFinal in epsilonNFA.FinalStates)
{
if (state.Contains(nfaFinal.ToString()))
{
finalStates.Add(state);
}
}
}
return(new DFA(reconstructedStates, epsilonNFA.Inputs, transitionFunctions, startState, finalStates));
}
