public static IRing <int> Part0(IRing <int> ring, IEnumerable <int> lengths, int iterations = 1)
{
var r = ring.Select(x => x).ToRing();
var current = 0;
var skip = 0;
var lengthsList = lengths.ToList();
foreach (var _ in Enumerable.Range(0, iterations))
{
foreach (var i in lengthsList)
{
var range = Enumerable.Range(current, i).ToList();
var slice = range.ConvertAll(j => r[j]);
slice.Reverse();
var sidx = 0;
foreach (var j in range)
{
r[j] = slice[sidx++];
}
current += i + skip;
++skip;
}
}
return(r);
}