Sha256: 5557c0f891385636e9c78ceb5d417df63b1736d9120b41cfb8be1d7f2091cb67
Contents?: true
Size: 1.18 KB
Versions: 396
Compression:
Stored size: 1.18 KB
Contents
using System;
using System.Linq;
public class RailFenceCipher
{
private readonly int _rails;
private readonly int _size;
public RailFenceCipher(int rails)
{
_rails = rails;
_size = rails * 2 - 2;
}
public string Encode(string input)
{
return input
.Select((c, i) => Tuple.Create(Track(i), c))
.GroupBy(x => x.Item1)
.Select(x => new string(x.Select(y => y.Item2).ToArray()))
.Aggregate("", (acc, x) => acc + x);
}
public string Decode(string input)
{
return Enumerable.Range(0, input.Length)
.GroupBy(Track)
.SelectMany(x => x)
.Zip(input, Tuple.Create)
.OrderBy(x => x.Item1)
.Aggregate("", (s, tuple) => s + tuple.Item2);
}
private int Track(int index)
{
if (IsCorrect(index))
{
return 0;
}
if (IsCorrect(index - _rails + 1))
{
return _rails - 1;
}
return Enumerable.Range(1, _rails - 1).First(i => IsCorrect(index - i) || IsCorrect(index - _size + i));
}
private bool IsCorrect(int index) => index % _size == 0;
}
Version data entries
396 entries across 396 versions & 1 rubygems