use strict;
use warnings;
use 5.12.0;

my $len = 5;
my $max = $len - 1;

for my $p0 ( 0 .. $max ) {
    for my $p1 ( $p0+1 .. $max ) {
        for my $p2 ( $p1+1 .. $max ) {
            my $str = "0" x $len;
            substr $str, $p0, 1, '1';
            substr $str, $p1, 1, '1';
            substr $str, $p2, 1, '1';
            say "$str $p0 $p1 $p2";
        }
    }
}