#What is the largest integer whose digits are all different (and do no
+t include 0) that is divisible by each of its individual digits?
#Requirements:
# -- Integer
# -- Digits all different (largest possible would be 987654321)
# -- Divisible by each of individual digits
# note: 
#    this integer cannot contain the digit 5 if it also contains any e
+ven digit, 
#    because then the number would be divisible by 10, and the last di
+git would be 0
#    similarly, if the last digit is odd, it can't contain any other e
+ven digit.

use strict;
use warnings;

my $max_number = 987654321;
#my $max_number = 10000;
foreach ( 0 .. $max_number - 1 ) {
    my $test_number = $max_number - $_;
    print "number / 100000: " . $test_number/100000 . "\n" if $test_nu
+mber % 100000 == 0;
    if ( passes($test_number) ) {
        print "$test_number passes!\n"; 
        die;
    }
}

sub passes {
    my $test_number = shift() || die "no test number";
    my @digits = split("", $test_number);
    my %seen;
    my $last_digit;

    #fail if see the same digit twice.
    foreach (  @digits ) {
        return 0 if $_ == 0; #fail if contains 0
        return 0 if $seen{$_};
        $seen{$_} = 1;
    }
    #set the last digit
    $last_digit = $digits[$#digits];

    #fail if contains 5, and any other digit is even
    #or the last digit is 1, and any other digit is even 
    if ( $seen{5} || $last_digit % 2 == 1 ) {
        for ( qw(2 4 6 8) ) {
            return 0 if $seen{$_}; 
        }        
    }

    for ( keys %seen ) {
        return 0 unless $test_number % $_ == 0 ;
    }
    return 1;
}
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