private static train Merge(List <train> ttrs, char ch)
{
train ntr = new train();
int ibc = 0, iec = 0;
foreach (train tr in ttrs)
{
if (tr.cb != ch)
{
ibc++;
ntr.cb = tr.cb;
}
if (tr.ce != ch)
{
iec++;
ntr.ce = tr.ce;
}
foreach (char cch in tr.ccnt)
{
if (!ntr.ccnt.Contains(cch))
{
ntr.ccnt.Add(cch);
}
}
foreach (char mch in tr.cmid)
{
if (!ntr.cmid.Contains(mch))
{
ntr.cmid.Add(mch);
}
}
}
if (ibc > 1 || iec > 1)
{
return(ntr);
}
if (ibc == 1 && iec == 1 && ntr.cb == ntr.ce)
{
return(ntr);
}
int iwc = ttrs.Count - 2;
int iw = 1;
if (ibc == 0)
{
ntr.cb = ch;
iwc++;
}
if (iec == 0)
{
ntr.ce = ch;
iwc++;
}
while (iwc > 1)
{
iw = (int)(Math.BigMul(iw, iwc) % mdl);
iwc--;
}
foreach (train tr in ttrs)
{
iw = (int)(Math.BigMul(iw, tr.ways) % mdl);
}
ntr.ways = iw;
return(ntr);
}
public static string Solve(List <train> trains)
{
List <char> chs = new List <char>();
for (int i = 0; i < trains.Count; i++)
{
if (trains[i].ways == 0)
{
return("0");
}
foreach (char mch in trains[i].cmid)
{
for (int j = 0; j < trains.Count; j++)
{
if (i == j)
{
continue;
}
if (trains[j].ccnt.Contains(mch))
{
return("0");
}
}
}
foreach (char ch in trains[i].ccnt)
{
if (!chs.Contains(ch))
{
chs.Add(ch);
}
}
}
foreach (char ch in chs)
{
List <train> ttrs = trains.FindAll(t => t.ccnt.Contains(ch));
train ntr = Merge(ttrs, ch);
if (ntr.ways == 0)
{
return("0");
}
foreach (train tr in ttrs)
{
trains.Remove(tr);
}
trains.Add(ntr);
}
int iw = 1;
int iwc = trains.Count;
while (iwc > 1)
{
//iw = (iw * iwc) % mdl;
iw = (int)(Math.BigMul(iw, iwc) % mdl);
iwc--;
}
foreach (train tr in trains)
{
iw = (int)(Math.BigMul(iw, tr.ways) % mdl);
//iw = (iw * tr.ways) % mdl;
}
return(iw.ToString());
}