private static SatProblem SubstituteVaraible(SatProblem problem, Variable variable, bool value)
{
SatProblem result = new SatProblem();
foreach (var clause in problem)
{
if (clause.TryGetValue(variable, out bool negated))
{
if (negated != value)
{
result.Add(new Clause());
}
else if (clause.Count > 1)
{
Clause newClause = new Clause(clause);
newClause.Remove(variable);
result.Add(newClause);
}
}
else
{
result.Add(new Clause(clause));
}
}
return(result);
}
public static SatProblem Parse(string filePath)
{
SatProblem result = new SatProblem();
using (StreamReader reader = new StreamReader(filePath))
{
Variable[] variables = null;
Clause clause = new Clause();
string line;
while ((line = reader.ReadLine()) != null)
{
if (line.StartsWith("c"))
{
continue;
}
if (line.StartsWith("p"))
{
var match = ProblemLineRegex.Match(line);
if (match.Success && int.TryParse(match.Groups["VariableCount"].Value, out int variableCount))
{
variables = new Variable[variableCount];
for (int i = 0; i < variableCount; i++)
{
variables[i] = new Variable(i);
}
}
else
{
throw new Exception($"Could not parse problem line of file {filePath}");
}
}
else if (variables != null)
{
var match = DataLineRegex.Match(line);
if (!match.Success)
{
continue;
}
foreach (Capture capture in match.Groups["Date"].Captures)
{
if (int.TryParse(capture.Value, out int value))
{
if (value == 0)
{
result.Add(clause);
clause = new Clause();
}
else
{
clause.Add(variables[Math.Abs(value) - 1], value < 0);
}
}
}
}
}
if (clause.Count > 0)
{
result.Add(clause);
}
return(result);
}
}
