Note that you can cut the time in half or there abouts by adding just two simple checks; this version of your program runs in 6.1 seconds on my machine - the original without the initial 9-digit loop takes 13 seconds on my machine:

use Algorithm::Loops qw( NextPermuteNum ); my @digs= (1..9); my @map; @map[1..9]= reverse 1..9; my $prev= 0; for my $len ( reverse 1..8 ) { do { my $num= substr( join( '', @map[ @digs ] ), 0, $len ); if( $num != $prev and $num !~ /[2468].*[13579]$/ and $num !~ / +5./) { for( $num =~ /./g, 0 ) { die "$num\n" if ! $_; last if 0 != $num % $_; } } $prev= $num; } while( NextPermuteNum(@digs) ); }

Note that all I've done is add two regex tests - that you don't have any even digits if the last digit is odd, and that you never have a 5 in any but the last position.

Reducing the search space is almost always a good idea.

--
@/=map{[/./g]}qw/.h_nJ Xapou cets krht ele_ r_ra/; map{y/X_/\n /;print}map{pop@$_}@/for@/

In reply to Re^3: Puzzle: What is the largest integer ... (not "a longest") by fizbin
in thread Puzzle: What is the largest integer whose digits are all different (and do not include 0) that is divisible by each of its individual digits? by tphyahoo

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