static bool FindYWings(Region region)
{
var points = region.Points.Where(p => puzzle[p].Candidates.Count == 2).ToArray();
if (points.Length > 1)
{
for (int i = 0; i < points.Length; i++)
{
SPoint p1 = points[i];
for (int j = i + 1; j < points.Length; j++)
{
SPoint p2 = points[j];
var inter = puzzle[p1].Candidates.Intersect(puzzle[p2].Candidates);
if (inter.Count() != 1)
{
continue;
}
int other1 = puzzle[p1].Candidates.Except(inter).ElementAt(0),
other2 = puzzle[p2].Candidates.Except(inter).ElementAt(0);
SPoint[] a = { p1, p2 };
foreach (SPoint point in a)
{
var p3a = puzzle[point].GetCanSeePoints().Except(points).Where(p => puzzle[p].Candidates.Count == 2 && puzzle[p].Candidates.Intersect(new int[] { other1, other2 }).Count() == 2);
if (p3a.Count() == 1) // Example: p1 and p3 see each other, so remove similarities from p2 and p3
{
SPoint p3 = p3a.ElementAt(0);
SPoint pOther = a.Single(p => p != point);
var common = puzzle[pOther].GetCanSeePoints().Intersect(puzzle[p3].GetCanSeePoints());
var cand = puzzle[pOther].Candidates.Intersect(puzzle[p3].Candidates); // Will just be 1 candidate
if (puzzle.ChangeCandidates(common, cand))
{
Logger.Log("Y-Wing", new SPoint[] { p1, p2, p3 }, cand);
return(true);
}
}
}
}
}
}
return(false);
}
static bool FindXYZWings(Region region)
{
bool changed = false;
var points2 = region.Points.Where(p => puzzle[p].Candidates.Count == 2).ToArray();
var points3 = region.Points.Where(p => puzzle[p].Candidates.Count == 3).ToArray();
if (points2.Length > 0 && points3.Length > 0)
{
for (int i = 0; i < points2.Length; i++)
{
SPoint p2 = points2[i];
for (int j = 0; j < points3.Length; j++)
{
SPoint p3 = points3[j];
if (puzzle[p2].Candidates.Intersect(puzzle[p3].Candidates).Count() != 2)
{
continue;
}
var p3Sees = puzzle[p3].GetCanSeePoints().Except(region.Points)
.Where(p => puzzle[p].Candidates.Count == 2 && // If it has 2 candidates
puzzle[p].Candidates.Intersect(puzzle[p3].Candidates).Count() == 2 && // Shares them both with p3
puzzle[p].Candidates.Intersect(puzzle[p2].Candidates).Count() == 1); // And shares one with p2
foreach (SPoint p2_2 in p3Sees)
{
var allSee = puzzle[p2].GetCanSeePoints().Intersect(puzzle[p3].GetCanSeePoints()).Intersect(puzzle[p2_2].GetCanSeePoints());
var allHave = puzzle[p2].Candidates.Intersect(puzzle[p3].Candidates).Intersect(puzzle[p2_2].Candidates); // Will be 1 Length
if (puzzle.ChangeCandidates(allSee, allHave))
{
Logger.Log("XYZ-Wing", new SPoint[] { p2, p3, p2_2 }, allHave);
changed = true;
}
}
}
}
}
return(changed);
}
static bool FindLockedCandidates(bool doRows, int rc, int value)
{
var with = (doRows ? Puzzle.Rows : Puzzle.Columns)[rc].GetPointsWithCandidates(value);
// Even if a block only has these candidates for this "k" value, it'd be slower to check that before cancelling "BlacklistCandidates"
if (with.Count() == 3 || with.Count() == 2)
{
var blocks = with.Select(p => puzzle[p].Block).Distinct();
if (blocks.Count() == 1)
{
if (puzzle.ChangeCandidates(Puzzle.Blocks[blocks.ElementAt(0)].Points.Except(with), new int[] { value }))
{
Logger.Log("Locked candidate", with, "{4} {0} locks within block {1}: {2}: {3}", doRows ? SPoint.RowL(rc) : (rc + 1).ToString(), blocks.ElementAt(0) + 1, with.Print(), value, doRows ? "Row" : "Column");
return(true);
}
}
}
return(false);
}
static bool PointingTuple()
{
for (int i = 0; i < 3; i++)
{
SPoint[][] blockrow = new SPoint[3][], blockcol = new SPoint[3][];
for (int r = 0; r < 3; r++)
{
blockrow[r] = Puzzle.Blocks[r + (i * 3)].Points;
blockcol[r] = Puzzle.Blocks[i + (r * 3)].Points;
}
for (int r = 0; r < 3; r++) // 3 blocks in a blockrow/blockcolumn
{
int[][] rowCand = new int[3][], colCand = new int[3][];
for (int j = 0; j < 3; j++) // 3 rows/columns in block
{
// The 3 cells' candidates in a block's row/column
rowCand[j] = blockrow[r].GetRow(j).Select(p => puzzle[p].Candidates).UniteAll().ToArray();
colCand[j] = blockcol[r].GetColumn(j).Select(p => puzzle[p].Candidates).UniteAll().ToArray();
}
// Now check if a row has a distinct candidate
var zero_distinct = rowCand[0].Except(rowCand[1]).Except(rowCand[2]);
if (zero_distinct.Count() > 0)
{
if (RemovePointingTuple(blockrow, true, i, r, 0, zero_distinct))
{
return(true);
}
}
var one_distinct = rowCand[1].Except(rowCand[0]).Except(rowCand[2]);
if (one_distinct.Count() > 0)
{
if (RemovePointingTuple(blockrow, true, i, r, 1, one_distinct))
{
return(true);
}
}
var two_distinct = rowCand[2].Except(rowCand[0]).Except(rowCand[1]);
if (two_distinct.Count() > 0)
{
if (RemovePointingTuple(blockrow, true, i, r, 2, two_distinct))
{
return(true);
}
}
// Now check if a column has a distinct candidate
zero_distinct = colCand[0].Except(colCand[1]).Except(colCand[2]);
if (zero_distinct.Count() > 0)
{
if (RemovePointingTuple(blockcol, false, i, r, 0, zero_distinct))
{
return(true);
}
}
one_distinct = colCand[1].Except(colCand[0]).Except(colCand[2]);
if (one_distinct.Count() > 0)
{
if (RemovePointingTuple(blockcol, false, i, r, 1, one_distinct))
{
return(true);
}
}
two_distinct = colCand[2].Except(colCand[0]).Except(colCand[1]);
if (two_distinct.Count() > 0)
{
if (RemovePointingTuple(blockcol, false, i, r, 2, two_distinct))
{
return(true);
}
}
}
}
return(false);
}
