Anonymous user
Run-length encoding: Difference between revisions
→Linq: Added StringBuilder version
(→Linq: Updated short linq solution to match) |
(→Linq: Added StringBuilder version) |
||
Line 764:
Encode(raw) = encoded = [12,W],[1,B],[12,W],[3,B],[24,W],[1,B],[14,W]
Decode(encoded) = WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW
Decode(Encode(raw)) = True
</pre>
Stringbuilder version. Might be more performant but mixes output formatting with encoding/decoding logic.
<!--Martin Freedman 22/02/2018-->
<lang csharp>using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Linq.Enumerable;
namespace RunLengthEncoding
{
static class Program
{
public static string Encode(string input) => input.Length == 0 ? "" : input.Skip(1)
.Aggregate((len: 1, chr: input[0], sb: new StringBuilder()),
(a, c) => a.chr == c ? (a.len + 1, a.chr, a.sb)
: (1, c, a.sb.Append($"{a.len}{a.chr}")),
a => a.sb.Append($"{a.len}{a.chr}"))
.ToString();
public static string Decode(string input) => input
.Aggregate((t: "", sb: new StringBuilder()),
(a, c) => !char.IsDigit(c) ? ("", a.sb.Append(new string(c, int.Parse(a.t))))
: (a.t + c, a.sb))
.sb.ToString();
public static void Main(string[] args)
{
const string raw = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW";
const string encoded = "12W1B12W3B24W1B14W";
WriteLine($"raw = {raw}");
WriteLine($"encoded = {encoded}");
WriteLine($"Encode(raw) = encoded = {Encode(raw)}");
WriteLine($"Decode(encode) = {Decode(encoded)}");
WriteLine($"Decode(Encode(raw)) = {Decode(Encode(raw)) == raw}");
ReadLine();
}
}
}</lang>
Output:
<pre>raw = WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW
encoded = 12W1B12W3B24W1B14W
Encode(raw) = encoded = 12W1B12W3B24W1B14W
Decode(encode) = WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW
Decode(Encode(raw)) = True
</pre>
| |||