Solution.KnotHash C# (CSharp) Method

    int[] KnotHash(IEnumerable<int> input, int rounds) {
        var output = Enumerable.Range(0, 256).ToArray();

        var current = 0;
        var skip = 0;
        for (var round = 0; round < rounds; round++) {
            foreach (var len in input) {
                for (int i = 0; i < len / 2; i++) {
                    var from = (current + i) % output.Length;
                    var to = (current + len - 1 - i) % output.Length;
                    (output[from], output[to]) = (output[to], output[from]);
                }
                current += len + skip;
                skip++;
            }
        }
        return output;
    }
}