public TekHeuristic(string description, HeuristicAction action) : this()
{
_description = description;
_action = action;
HeuristicFields = new List <TekField>();
AffectedFields = new List <TekField>();
HeuristicValues = new List <int>();
Enabled = true;
}
private HeuristicAction TryValue(TekBoard board, TekField field, int value)
{
bool prev = board.EatExceptions;
HeuristicAction result = HeuristicAction.haNone;
try
{
board.EatExceptions = false;
this.Enabled = false; // make sure FindHeuristic doesnt call this recursively!
if ((result = _tryValue(field, value)) == HeuristicAction.haNone)
{
temStoredResults.Clear();
temMoves.TakeSnapshot(_ssDescription(field));
try {
do
{
try
{
result = _tryHeuristic(heuristics.FindHeuristic(board), board);
}
catch (ETekFieldInvalid)
{
result = HeuristicAction.haImpossible;
}
} while (result == HeuristicAction.haNone);
}
finally
{
temMoves.RestoreSnapshot(_ssDescription(field));
_ssIndex++;
}
}
}
finally
{
board.EatExceptions = prev;
this.Enabled = true;
field.Value = 0; // backtracking
}
return(result);
}
public override bool HeuristicApplies(TekBoard board, TekField field)
{
HeuristicAction action = HeuristicAction.haNone;
HeuristicAction found = HeuristicAction.haNone;
HeuristicValues.Clear(); // clear any values already set
foreach (int value in new List <int>(field.PossibleValues)) // can't use the list directly in foreach
{
switch (action = TryValue(board, field, value))
{
case HeuristicAction.haSetValue:
HeuristicValues.Clear();
AddValue(value);
found = action;
break;
case HeuristicAction.haExcludeValue:
AddValue(value);
found = action;
break;
}
if (action == HeuristicAction.haSetValue) // solution found, so we can stop
{
break;
}
// if you haven't found a solution, it doesnt hurt to continue maybe you can find a solution
// or maybe you can add a second value to exclude
}
if (found == HeuristicAction.haSetValue || found == HeuristicAction.haExcludeValue)
{
SetHeuristicAction(found);
AddHeuristicField(field);
AddAffectedField(field);
}
return(AffectedFields.Count > 0);
}
protected void SetHeuristicAction(HeuristicAction value)
{
_action = value;
}
