Data commit

Task/Self-numbers/C-sharp/self-numbers.cs

@@ -0,0 +1,33 @@
+using System;
+using static System.Console;
+
+class Program {
+
+  const int mc = 103 * 1000 * 10000 + 11 * 9 + 1;
+
+  static bool[] sv = new bool[mc + 1];
+
+  static void sieve() { int[] dS = new int[10000];
+    for (int a = 9, i = 9999; a >= 0; a--)
+      for (int b = 9; b >= 0; b--)
+        for (int c = 9, s = a + b; c >= 0; c--)
+          for (int d = 9, t = s + c; d >= 0; d--)
+            dS[i--] = t + d;
+    for (int a = 0, n = 0; a < 103; a++)
+      for (int b = 0, d = dS[a]; b < 1000; b++, n += 10000)
+        for (int c = 0, s = d + dS[b] + n; c < 10000; c++)
+          sv[dS[c] + s++] = true; }
+
+  static void Main() { DateTime st = DateTime.Now; sieve();
+    WriteLine("Sieving took {0}s", (DateTime.Now - st).TotalSeconds);
+    WriteLine("\nThe first 50 self numbers are:");
+    for (int i = 0, count = 0; count <= 50; i++) if (!sv[i]) {
+        count++; if (count <= 50) Write("{0} ", i);
+        else WriteLine("\n\n       Index     Self number"); }
+    for (int i = 0, limit = 1, count = 0; i < mc; i++)
+      if (!sv[i]) if (++count == limit) {
+          WriteLine("{0,12:n0}   {1,13:n0}", count, i);
+          if (limit == 1e9) break; limit *= 10; }
+    WriteLine("\nOverall took {0}s", (DateTime.Now - st). TotalSeconds);
+  }
+}