note
TedPride
<code>
use strict;
use warnings;
print nearPrime(100000);
sub nearPrime {
my $num = shift; $_ = 0;
return $num if isPrime($num);
while (1) {
$_++;
return ($num - $_) if isPrime($num - $_);
return ($num + $_) if isPrime($num + $_);
}
}
BEGIN {
my @primes = (2); my $max = 2;
sub isPrime {
my $num = shift;
my $root = int sqrt $num;
if ($root > $max) {
for (($max+1)..$root) {
push(@primes, $_) if isPrime($_);
}
$max = $root;
}
for (@primes) {
return 0 if ($num % $_ == 0);
}
return 1;
}
}
</code>
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