public CompoundFormula ToCNF2()
{
if (IsSimpleFormula())
return this;
if (IsCNF())
return this;
if (IsSimpleDisjunction())
{
CompoundFormula cfAnd = new CompoundFormula("and");
cfAnd.AddOperand(this);
return cfAnd;
}
bool bChanged = true;
CompoundFormula cfRevised = new CompoundFormula(Operator);
List<CompoundFormula> lSimpleOneOf = new List<CompoundFormula>();
foreach (Formula f in Operands)
{
if (f is CompoundFormula)
{
CompoundFormula cf = (CompoundFormula)f;
if (cf.IsSimpleOneOf())
lSimpleOneOf.Add(cf);
else
cfRevised.AddOperand(((CompoundFormula)f).RemoveOneof(out bChanged));
}
else
cfRevised.AddOperand(f);
}
cfRevised = (CompoundFormula)cfRevised.Simplify();
bChanged = true;
while (bChanged)
{
bChanged = false;
cfRevised = (CompoundFormula)cfRevised.RemoveNestedConjunction(out bChanged);
}
/*
if (cfRevised.Operator != "and")
{
CompoundFormula cfAnd = new CompoundFormula("and");
cfAnd.AddOperand(cfRevised);
cfRevised = cfAnd;
}
*/
foreach (CompoundFormula cf in lSimpleOneOf)
cfRevised.AddOperand(cf);
Debug.Assert(cfRevised.IsCNF());
return cfRevised;
}
