/// Returns new patterns
public List <TictactoeSituation> SetIncidentalsAndReturnNew(TictactoeSituation ts, HashSet <TictactoeSituation> tsHash)
{
var newNodes = new List <TictactoeSituation>();
var nextStone = ts.StoneCount % 2 == 0? Stone.Black : Stone.White;
var curr = new HashSet <TictactoeSituation>();
for (var i = 0; i < Rows; i++)
{
for (var j = 0; j < Cols; j++)
{
if (ts.Stones[i, j] == Stone.None)
{
var n = ts.Stones.Copy();
if (CheckWin(n, i, j, nextStone, WinningLen))
{
ts.SetVerdict(nextStone == Stone.Black ? VerdictResult.BlackSecured : VerdictResult.WhiteSecured);
ts.Indicdentals.Clear();
foreach (var nn in newNodes)
{
tsHash.Remove(nn);
}
return(null);
}
n[i, j] = nextStone;
if (CheckTie(n, WinningLen))
{
ts.SetVerdict(VerdictResult.TiePossible);
ts.Indicdentals.Clear();
foreach (var nn in newNodes)
{
tsHash.Remove(nn);
}
return(null);
}
var tsIn = new TictactoeSituation(n);
if (!curr.Contains(tsIn))
{
if (!tsHash.TryGetValue(tsIn, out var tsOut))
{
tsHash.Add(tsIn);
newNodes.Add(tsIn);
tsOut = tsIn;
}
ts.AddIncidental(tsOut);
curr.Add(tsOut);
}
}
}
}
return(newNodes);
}
public IEnumerable <TictactoeSituation> GenerateTree()
{
var z = new TictactoeSituation(new Stone[Rows, Cols]);
yield return(z);
var id = 0;
z.Id = id++;
var hashLevel = 1;
var tshash = new HashSet <TictactoeSituation>();
var q = new Queue <TictactoeSituation>();
q.Enqueue(z);
while (q.Count > 0)
{
var p = q.Dequeue();
if (p.StoneCount + 1 > hashLevel)
{
tshash.Clear();
hashLevel = p.StoneCount + 1;
}
var newItems = SetIncidentalsAndReturnNew(p, tshash);
if (newItems != null)
{
foreach (var newItem in newItems)
{
newItem.Id = id++;
q.Enqueue(newItem);
yield return(newItem);
}
}
foreach (var c in p.Indicdentals)
{
System.Diagnostics.Debug.Assert(c.Id != 0);
}
}
}
public void AddIncidental(TictactoeSituation ts)
{
Indicdentals.Add(ts);
ts.Parents.Add(this);
}