protected override void OperateOn(SudokuModel model)
{
for (var iType = 0; iType < 3; ++iType) {
var type = (RegionType)iType;
for (var i = 0; i < model.Size; ++i) {
var region = new Region(type, i);
var tuple = new Tuple<SudokuModel, Region>(model, region);
if (GetCheckedIteration(tuple) < model.GetLastChangedIterRegion(type, i)) {
_checkedIteration[tuple] = model.ChangeCount;
foreach (var unsolved in model.GetUnsolvedValues(type, i)) {
var timesFound = 0;
Cell? foundAt = null;
foreach (var cell in model.GetCells(type, i)) {
if ((model.GetPossibilitySetCell(cell.Column, cell.Row) & (1 << unsolved)) != 0) {
++timesFound;
foundAt = cell;
if (timesFound > 1) {
break;
}
}
}
if (timesFound == 1) {
if (foundAt != null) {
model.SetValueOptimized(foundAt.Value.Column, foundAt.Value.Row, unsolved, type, i);
}
}
}
}
}
}
}
protected override void OperateOn(SudokuModel model)
{
// We could look at all 2^N possible sets on all 3N of the model's regions,
// but it is more efficient to only use the
// possiblity set of each cell, and isolate that set on each intersecting region.
for (var row = 0; row < model.Size; ++row) {
for (var col = 0; col < model.Size; ++col) {
if (!model.IsSolved(col, row)) {
foreach (var region in model.GetIntersectingRegions(col, row)) {
var checkedIter = GetCheckedIteration(region);
if (checkedIter < model.GetLastChangedIterRegion(region.Type, region.I)) {
_checkedIteration[region] = checkedIter;
IsolateSet(model.GetPossibilitySetCell(col, row), region, model);
}
}
}
}
}
}
