Initial data commit

Task/Power-set/C-sharp/power-set-1.cs

@@ -0,0 +1,20 @@
+public IEnumerable<IEnumerable<T>> GetPowerSet<T>(List<T> list)
+{
+    return from m in Enumerable.Range(0, 1 << list.Count)
+                  select
+                      from i in Enumerable.Range(0, list.Count)
+                      where (m & (1 << i)) != 0
+                      select list[i];
+}
+
+public void PowerSetofColors()
+{
+    var colors = new List<KnownColor> { KnownColor.Red, KnownColor.Green,
+        KnownColor.Blue, KnownColor.Yellow };
+
+    var result = GetPowerSet(colors);
+
+    Console.Write( string.Join( Environment.NewLine,
+        result.Select(subset =>
+            string.Join(",", subset.Select(clr => clr.ToString()).ToArray())).ToArray()));
+}

Task/Power-set/C-sharp/power-set-2.cs

@@ -0,0 +1,7 @@
+  public IEnumerable<IEnumerable<T>> GetPowerSet<T>(IEnumerable<T> input) {
+    var seed = new List<IEnumerable<T>>() { Enumerable.Empty<T>() }
+      as IEnumerable<IEnumerable<T>>;
+
+    return input.Aggregate(seed, (a, b) =>
+      a.Concat(a.Select(x => x.Concat(new List<T>() { b }))));
+  }

Task/Power-set/C-sharp/power-set-3.cs

@@ -0,0 +1,23 @@
+  using System;
+  class Powerset
+  {
+    static int count = 0, n = 4;
+    static int [] buf = new int [n];
+
+    static void Main()
+    {
+  	int ind = 0;
+  	int n_1 = n - 1;
+  	for (;;)
+  	{
+  	  for (int i = 0; i <= ind; ++i) Console.Write("{0, 2}", buf [i]);
+  	  Console.WriteLine();
+  	  count++;
+
+  	  if (buf [ind] < n_1) { ind++; buf [ind] = buf [ind - 1] + 1; }
+  	  else if (ind > 0) { ind--; buf [ind]++; }
+  	  else break;
+  	}
+  	Console.WriteLine("n=" + n + "   count=" + count);
+    }
+  }

Task/Power-set/C-sharp/power-set-4.cs

@@ -0,0 +1,22 @@
+using System;
+class Powerset
+{
+  static int n = 4;
+  static int [] buf = new int [n];
+
+  static void Main()
+  {
+    rec(0, 0);
+  }
+
+  static void rec(int ind, int begin)
+  {
+    for (int i = begin; i < n; i++)
+    {
+      buf [ind] = i;
+      for (int j = 0; j <= ind; j++) Console.Write("{0, 2}", buf [j]);
+      Console.WriteLine();
+      rec(ind + 1, buf [ind] + 1);
+    }
+  }
+}