/// <inheritdoc/>
public override void GetAll(IBag <TechniqueInfo> accumulator, IReadOnlyGrid grid)
{
var r = (Span <int>) stackalloc int[2];
foreach (var((baseSet, coverSet), (a, b, c)) in IntersectionMaps)
{
if (!EmptyMap.Overlaps(c))
{
continue;
}
short m1 = BitwiseOrMasks(grid, a);
short m2 = BitwiseOrMasks(grid, b);
short m3 = BitwiseOrMasks(grid, c);
short m = (short)(m3 & (m1 ^ m2));
if (m == 0)
{
continue;
}
foreach (int digit in m.GetAllSets())
{
GridMap elimMap;
(r[0], r[1], elimMap) =
a.Overlaps(CandMaps[digit])
? (coverSet, baseSet, a & CandMaps[digit])
: (baseSet, coverSet, b & CandMaps[digit]);
if (elimMap.IsEmpty)
{
continue;
}
var conclusions = new List <Conclusion>();
foreach (int cell in elimMap)
{
conclusions.Add(new Conclusion(Elimination, cell, digit));
}
var candidateOffsets = new List <(int, int)>();
foreach (int cell in c& CandMaps[digit])
{
candidateOffsets.Add((0, cell * 9 + digit));
}
accumulator.Add(
new LcTechniqueInfo(
conclusions,
views: new[]
/// <summary>
/// Search for all W-Wings.
/// </summary>
/// <param name="result">The result accumulator.</param>
/// <param name="grid">The grid.</param>
/// <returns>All technique information instances.</returns>
public static void TakeAllWWings(IBag <TechniqueInfo> result, IReadOnlyGrid grid)
{
if (BivalueMap.Count < 2)
{
return;
}
// Iterate on each cells.
for (int c1 = 0; c1 < 72; c1++)
{
if (!BivalueMap[c1] || !EmptyMap[c1])
{
continue;
}
// Iterate on each cells which are not peers in 'c1'.
int[] digits = grid.GetCandidatesReversal(c1).GetAllSets().ToArray();
foreach (int c2 in BivalueMap - new GridMap(c1))
{
if (c2 < c1 || grid.GetCandidatesReversal(c1) != grid.GetCandidatesReversal(c2))
{
continue;
}
var intersection = new GridMap(c1, false) & new GridMap(c2, false);
if (!EmptyMap.Overlaps(intersection))
{
continue;
}
for (int region = 9; region < 27; region++)
{
if (region < 18 && (
GetRegion(c1, RegionLabel.Row) == region || GetRegion(c2, RegionLabel.Row) == region) ||
region >= 18 && (
GetRegion(c1, RegionLabel.Column) == region || GetRegion(c2, RegionLabel.Column) == region))
{
continue;
}
SearchWWingByRegions(result, grid, digits, region, c1, c2, intersection);
}
}
}
}
