Project Euler 27

PE27.pl

#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

sub is_prime{
    my $n = shift;

    return 0 if $n < 2;
    return 0 if $n % 2 == 0 && $n > 2;
    
    for(my $i = 3; $i*$i <= $n; $i += 2){
	return 0 if $n % $i == 0;
    }
    return 1;
}

sub seq_prime_count{
    my ($a, $b) = @_;
    my $n = 0;

    while( is_prime($n**2 + $a*$n + $b) ){
	$n++;
    }
    return $n;
}

my ($a, $b);
my $mx = 0;

foreach my $j (2..999){
    foreach my $i ((1-$j)..999){
	my $tmp = seq_prime_count($i, $j);
	if( $mx < $tmp ){
	    $mx = $tmp;
	    ($a, $b) = ($i, $j);
	}
    }
}
print $a * $b,"\n";
# => -59231
# ぜんぜんperlっぽくないな…