Simpler version for arbitrarilly large numbers.

challenge-059/jaredor/perl/ch-2.pl

@@ -4,46 +4,35 @@
 use warnings;
 use bigint;
 use Config;
-use List::Util qw(all sum max);
+use List::Util qw(all sum);
 
 # PWC 059, TASK #2 : Bit Sum
 
 # Answer based on perl doc for unpack and www.perlmonks.org/?node_id=407933
 
-my ( $LL, $NN ) =
-  defined $Config{longlongsize}
-  ? ( 8 * $Config{longlongsize}, 'Q' )
-  : ( 8 * $Config{longsize}, 'L' );
-
-my $CHOP_SIZE = 2**${LL};
-my $CHOP_ZERO = pack "${NN}", 0;
-
 die "This script requires one or more positive integer arguments."
   unless @ARGV;
 
 die "Not all arguments to the script are positive integers."
   unless all { /\A [1-9] \d* \Z/xms } @ARGV;
 
-#my @nums = map { pack "${NN}*", $_ } @ARGV;
+my ( $LL, $NN ) =
+  defined $Config{longlongsize}
+  ? ( 8 * $Config{longlongsize}, 'Q' )
+  : ( 8 * $Config{longsize}, 'L' );
+
+my $WORD = 2**$LL;
 
-sub chop_up {
-    my ( $num, @chopped ) = ( 0 + $_[0], );
-    while ($num) {
-        push @chopped, $num % $CHOP_SIZE;
-        $num = int( $num / $CHOP_SIZE );
-    }
-    return [ map { pack "${NN}", $_ } @chopped ];
+sub num2bitstr {
+    my ( $numstr, $bitstr ) = ( $_[0], );
+    $bitstr .= pack "${NN}", $numstr % $WORD and $numstr /= $WORD while $numstr;
+    return $bitstr;
 }
 
-my @nums  = map     { chop_up $_ } @ARGV;
-my $chops = max map { $#$_ } @nums;
-( $chops - $#$_ ) and push @$_, ($CHOP_ZERO) x ( $chops - $#$_ ) for @nums;
+my @nums = map { num2bitstr $_ } @ARGV;
 
-my ( @diffbits, $numa );
-while ( $numa = shift @nums ) {
-    for my $numb (@nums) {
-        push @diffbits, unpack( "%${LL}b*", $numa->[$_] ^ $numb->[$_] )
-          for 0 .. $chops;
-    }
+my ( @diffbits, $num );
+while ( $num = pop @nums ) {
+    push @diffbits, unpack( "%${LL}b*", $num ^ $_ ) for @nums;
 }
 say @diffbits ? sum @diffbits : 0;