Self numbers: Difference between revisions
added C# version, translation of Pascal, but stripped down.
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(added C# version, translation of Pascal, but stripped down.) |
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;*[[wp:Self_number|Wikipedia: Self numbers]]
=={{header|C#|CSharp}}==
{{trans|Pascal}} Stripped down, as C# limits the size of an array to Int32.MaxValue, so the sieve isn't large enough to hit the 1,000,000,000th value.
<lang csharp>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);
}
}</lang>
{{out}}
<pre>Sieving took 3.4266187s
The first 50 self numbers are:
1 3 5 7 9 20 31 42 53 64 75 86 97 108 110 121 132 143 154 165 176 187 198 209 211 222 233 244 255 266 277 288 299 310 312 323 334 345 356 367 378 389 400 411 413 424 435 446 457 468
Index Self number
1 1
10 64
100 973
1,000 10,188
10,000 102,225
100,000 1,022,675
1,000,000 10,227,221
10,000,000 102,272,662
100,000,000 1,022,727,208
Overall took 7.0237244s</pre>
=={{header|F_Sharp|F#}}==
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