/// <summary>
/// Edge(s, symbol) - A collection of NfaState which can be shifted from s when accepting symbol
/// </summary>
/// <see cref="https://www.cnblogs.com/Ninputer/archive/2011/06/10/2077991.html"/>
/// <param name="s">the starting state</param>
/// <param name="symbol">the accepted symbol</param>
/// <returns>All the states shifted from s</returns>
public static HashSet <NfaState> Edge(NfaState s, int symbol)
{
var resultSet = new HashSet <NfaState>(s.EdgesToOther.Count);
var checkingList = new List <NfaEdge>(s.EdgesToOther);
while (checkingList.Count != 0)
{
var toCheck = checkingList[0];
checkingList.Remove(toCheck);
if (toCheck.Sym != symbol)
{
continue;
}
resultSet.Add(toCheck.Target);
}
return(resultSet);
}
public static HashSet <NfaState> Closure(NfaState s)
{
var closure = new HashSet <NfaState>(s.EdgesToOther.Count);
var checkingList = new List <NfaEdge>(s.EdgesToOther);
while (checkingList.Count != 0)
{
var toCheck = checkingList[0];
checkingList.Remove(toCheck);
if (toCheck.Sym != NfaEdge.SymEpsilon)
{
continue;
}
closure.Add(toCheck.Target);
checkingList.AddRange(toCheck.Target.EdgesToOther);
}
return(closure);
}
public NfaEdge(int symbol, NfaState targetState)
{
Sym = symbol;
Target = targetState;
}