public static XElement getShortestFeedback(XElement regex, XElement xAlphabet, XElement representative, XElement attemptShortest, XElement maxGrade)
{
int maxG = int.Parse(maxGrade.Value);
CharSetSolver solver = new CharSetSolver(BitWidth.BV64);
var dfaPair = DFAUtilities.parseRegexFromXML(regex, xAlphabet, solver);
var dfa = dfaPair.Second.Minimize(solver);
string representativeString = (XElement.Parse(DFAUtilities.RemoveAllNamespaces(representative.ToString()))).Value.Trim();
representativeString = representativeString.decodeEpsilon();
string attemptShortestString = (XElement.Parse(DFAUtilities.RemoveAllNamespaces(attemptShortest.ToString()))).Value.Trim();
attemptShortestString = attemptShortestString.decodeEpsilon();
int representativeState = DFAUtilities.GetStateAfterString(dfa.InitialState, representativeString, dfa, solver);
int attemptShortestState = DFAUtilities.GetStateAfterString(dfa.InitialState, attemptShortestString, dfa, solver);
xAlphabet = XElement.Parse(DFAUtilities.RemoveAllNamespaces(xAlphabet.ToString()));
HashSet <char> alphabet = parseAlphabet(xAlphabet);
string correctShortest = DFAUtilities.GetRepresentative(representativeState, dfa, alphabet, solver);
if (correctShortest.Equals(attemptShortestString))
{
return(XElement.Parse(string.Format("<div><grade>{0}</grade><feedback>Correct!</feedback></div>", maxG)));
}
else if (attemptShortestState == representativeState)
{
if (representativeString.Equals(attemptShortestString))
{
return(XElement.Parse(string.Format("<div><grade>{0}</grade><feedback>Please provide a different word than the given one</feedback></div>", 0)));
}
else if (attemptShortestString.Length > correctShortest.Length)
{
return(XElement.Parse(string.Format("<div><grade>{0}</grade><feedback>The word '{1}' is in the same equivalence class as '{2}' but there exists a shorter one</feedback></div>", (int)(maxG * 2 / 3), attemptShortestString.emptyToEpsilon(), representativeString.emptyToEpsilon())));
}
else
{
return(XElement.Parse(string.Format("<div><grade>{0}</grade><feedback>The word '{1}' is in the same equivalence class as '{2}' but there exists a <strong>lexicographically smaller</strong> one</feedback></div>", (int)(maxG * 4 / 5), attemptShortestString.emptyToEpsilon(), representativeString.emptyToEpsilon())));
}
}
else
{
string feedString = "Incorrect!";//"The Correct Answer is '" + correctShortest + "'";
return(XElement.Parse(string.Format("<div><grade>{0}</grade><feedback>{1}</feedback></div>", 0, feedString)));
}
}