#!/usr/bin/perl

use warnings;
use strict;

use payment;
my @my_bills = qw (200 100 50 20 10 5 2 1);

my @my_payments = qw{135 80 66 150 69};
my $mp          = payment->new();
$mp->change(@my_bills);

foreach (@my_payments) {
    $mp->add($_);
}

my %result = $mp->get();

foreach ( sort { $b <=> $a } keys(%result) ) {
    print "$_ \t: $result{$_}\n";
}

##</code><code>##

package payment;

use warnings;
use strict;

sub new {
    my $class = shift;
    my $self  = {};
    $self->{units} = undef;
    $self->{bills} = undef;
    bless $self, $class;
}

sub change {
    my $self = shift;
    @{ $self->{units} } = @_;
    %{ $self->{bills} } = map { $_ => 0 } @_;
}

sub add {
    my $self   = shift;
    my @units  = @{ $self->{units} };
    my %pieces = %{ $self->{bills} };

    my $temp = shift;
    my $unit;
    my $i = 0;
    while ($temp) {
        $unit = $units[$i];

        while ( $temp >= $unit ) {
            $temp -= $unit;
            $pieces{$unit} += 1;
        }
        last if $i == (@units);
        $unit = $units[ ++$i ];
    }
    %{ $self->{bills} } = %pieces;
}

sub get {
my $self = shift;
    return %{ $self->{bills}};
}

1;