public Tuple <List <int>, List <int> > FindPermutation(SlowBoard other)
{
if (!Degrees.Select(x => x.Item2).SequenceEqual(other.Degrees.Select(x => x.Item2)))
{
return(null);
}
var mappingPairs = new List <Tuple <List <int>, List <int> > >();
for (int i = 0; i < DegreeChangeIndices.Count - 1; i++)
{
var domain = new List <int>();
var codomain = new List <int>();
for (int j = DegreeChangeIndices[i]; j < DegreeChangeIndices[i + 1]; j++)
{
domain.Add(Degrees[j].Item1);
codomain.Add(other.Degrees[j].Item1);
}
mappingPairs.Add(new Tuple <List <int>, List <int> >(domain, codomain));
}
return(mappingPairs.Select(mp => Permutation.EnumerateAll(mp.Item2.Count).Select(p => new Tuple <List <int>, List <int> >(mp.Item1, p.Apply(mp.Item2))))
.CartesianProduct()
.Select(mapping => FlattenMapping(mapping))
.FirstOrDefault(mapping => SequenceEqualPermuted(mapping, other)));
}