Sha256: 128ca147ee324ede53913b83579a9357d290fb042f51e9465e34f9b1e4d770ef
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Versions: 73
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Contents
package Palindrome;
use strict;
use warnings;
sub new {
my ($class, $min_max) = @_;
my $self = {};
$self->{max_factor} = $min_max->{max_factor};
$self->{min_factor} = $min_max->{min_factor} || 1;
return bless $self, $class;
}
sub largest {
my $self = shift;
return $self->_filter_factors( sub { $_[0] > $_[1] } );
}
sub smallest {
my $self = shift;
return $self->_filter_factors( sub { $_[0] < $_[1] } );
}
sub _filter_factors {
my ($self, $filter) = @_;
my @all_factors = @{ _palindrome_factors( $self->{min_factor}, $self->{max_factor} ) };
my @factors = (shift @all_factors);
my $extreme_value = $factors[0]->[0] * $factors[0]->[1];
foreach my $f ( @all_factors ) {
my $value = $f->[0] * $f->[1];
if ($filter->($value, $extreme_value)) {
@factors = ($f,);
$extreme_value = $value;
next;
}
push @factors, [$f->[0], $f->[1]] if $value == $extreme_value;
}
return { value => $extreme_value, factors => \@factors };
}
sub _palindrome_factors {
my ($min, $max) = @_;
my $jmin = $min;
$max = $max;
my @factors;
foreach my $i ( $min..$max ) {
foreach my $j ( $jmin..$max ) {
my $value = $i * $j;
push @factors, [$i, $j] if _is_palindrome($value);
}
$jmin++;
}
return [@factors];
}
sub _is_palindrome {
my $input = shift;
return $input eq scalar(reverse $input);
}
1;
Version data entries
73 entries across 73 versions & 1 rubygems