Is this what you want, as tye pointed out, 
#!/usr/bin/perl -w
use strict;
use Smart::Comments '###';
my $report ={};

my @strings = qw(
0101
0001
);



for (@strings){
        my $string = $_;
        $report->{$_}++ for $string=~/../g;

}

### $report

### should be
### 01 3
### 00 1

[download]
Or should the result be 01=3x, 10=1x, 00=2x ?

In reply to Re: Speeding permutation counting by leocharre
in thread Speeding permutation counting by albert

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