Initial data commit

Task/Run-length-encoding/C-sharp/run-length-encoding-2.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+using System.Linq;
+using static System.Console;
+namespace RunLengthEncoding
+{
+    static class Program
+    {
+         public static string Encode(string input) => input.Length ==0 ? "" : input.Skip(1)
+            .Aggregate((t:input[0].ToString(),o:Empty<string>()),
+               (a,c)=>a.t[0]==c ? (a.t+c,a.o) : (c.ToString(),a.o.Append(a.t)),
+               a=>a.o.Append(a.t).Select(p => (key: p.Length, chr: p[0])));
+
+        public static string Decode(IEnumerable<(int i , char c)> input) =>
+            string.Concat(input.Select(t => new string(t.c, t.i)));
+
+        public static void Main(string[] args)
+        {
+            const string  raw = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW";
+            var encoded = new[] { (12, 'W'), (1, 'B'), (12, 'W'), (3, 'B'), (24, 'W'), (1, 'B'), (14, 'W') };
+
+            WriteLine($"raw = {raw}");
+            WriteLine($"Encode(raw) = encoded = {Encode(raw).TupleListToString()}");
+            WriteLine($"Decode(encoded) = {Decode(encoded)}");
+            WriteLine($"Decode(Encode(raw)) = {Decode(Encode(raw)) == raw}");
+            ReadLine();
+        }
+        private static string TupleListToString(this IEnumerable<(int i, char c)> list) =>
+            string.Join(",", list.Select(t => $"[{t.i},{t.c}]"));
+    }
+}