// returns start and end index (both inclusive) of mid word
private static TwoTuple <int, int> detectLoopFromState(StringDFA dfa, string currentState, string word, int n)
{
List <string> statesVisited = new List <string>();
if (!dfa.Accepts(word))
{
throw new PumpingLemmaException("Automaton does not accept this word!");
}
statesVisited.Add(currentState);
int currentLetter = 0;
while (currentLetter <= n && currentLetter < word.Length)
{
string newState = dfa.delta[new TwoTuple <string, string>(currentState, word.ElementAt(currentLetter) + "")];
if (statesVisited.Contains(newState))
{
int index = statesVisited.IndexOf(newState);
return(new TwoTuple <int, int>(index, currentLetter));
}
else
{
currentLetter++;
currentState = newState;
statesVisited.Add(currentState);
}
}
return(null);
}
public static int RegularGetI(StringDFA dfa, string start, string mid, string end)
{
if (!dfa.Accepts(start + end))
{
return(0);
}
if (RegularCheckSplit(dfa, start, mid, end))
{
return(1); //AI admits defeat
}
int i = 2;
while (dfa.Accepts(pumpMid(start, mid, end, i)))
{
i++;
//for debuugging purposes:
if (i > 99)
{
return(1);
}
}
return(i);
}
/*
* ----------------------------------------------------------------------------------------------------
* Decision Making
* ----------------------------------------------------------------------------------------------------
*/
public static string RegularCheckWord(StringDFA dfa, int n, string word)
{
if (word.Length < n)
{
return("<false>Word is too short.</false>");
}
foreach (char c in word)
{
if (!dfa.alphabet.Contains(c + ""))
{
return("<false>Word contains illegal letters.</false>");
}
}
if (dfa.Accepts(word))
{
return("<true></true>");
}
return("<false>Word is not in the language.</false>");
}
public static bool RegularCheckI(StringDFA dfa, string start, string mid, string end, int i)
{
return(dfa.Accepts(pumpMid(start, mid, end, i)));
}