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@sonnemaf
Created December 1, 2021 13:39
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var sw = System.Diagnostics.Stopwatch.StartNew();
int total = 0;
for (int i = 1; i <= 20_000_000; i++) {
if (IsPrime(i)) {
total++;
}
}
sw.Stop();
Console.WriteLine($"{total} in {sw.Elapsed} sec");
bool IsPrime(int number) {
if ((number % 2) == 0) {
return number == 2;
}
var sqrt = (int)Math.Sqrt(number);
for (int t = 3; t <= sqrt; t += 2) {
if ((number % t) == 0) {
return false;
}
}
return number > 1;
}
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