//
//places is the size of the array
// fills is the number of recursions
public static HashSet <dec> Permute(int places, int fills, HashSet <dec> set = null, int basis = 0)
{
if (set == null)
{
set = new HashSet <dec>();
}
//if places = 4 & fills = 1
//1000 0100 0010 0001
//if places = 3 & fills = 2
//110 101 011
for (int i = places - 1; i >= 0; i--)
{
if (((1 << i) | basis) == basis)
{
continue;
}
dec newVal = basis + (1 << i);
if (fills == 1)
{
set.Add(newVal);
}
else
{
Permute(places - 1, fills - 1, set, newVal);
}
}
return(set);
}
public static dec Add6And9(dec i)
{
dec six = 0b0000100000;
dec nine = 0b0100000000;
if ((i | six) == i || (i | nine) == i)
{
i = i | six;
i = i | nine;
}
return(i);
}
public static bool HasBoth(dec a, dec b)
{
dec[][] sqrs =
squares.Select(e => e.Select(z => IntToDecPos(z)).ToArray()).ToArray();
a = Add6And9(a);
b = Add6And9(b);
foreach (dec[] d in sqrs)
{
if ((a | d[0]) == a && (b | d[1]) == b)
{
continue;
}
if ((b | d[0]) == b && (a | d[1]) == a)
{
continue;
}
return(false);
}
return(true);
}