public static IArray <T> Flatten <T>(this IArray <IArray <T> > seqs)
{
IArray <long> tmp = seqs.Select(xs => xs.Count).PartialSums();
var r = new T[tmp.Last()];
tmp = tmp.DropSuffix(1);
for (int i = 0; i < seqs.Count; ++i)
{
seqs[i].CopyTo(r, (int)tmp[i]);
}
return(new ArrayAdapter <T>(r));
}
public static IArray <int> AdjacentDifferences(this IArray <int> self)
{
return(self.Skip(1).Zip(self.DropSuffix(1), (a, b) => a - b));
}