#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my $last_part = 1;
my (%part, %store);
while (my $line = <DATA>) {
    chomp $line;
    my @parts = split /\|/, $line;
    ! exists $part{$_} and $part{$_} = $last_part++ for @parts;
    my $string = 0 x ($last_part - 1);
    substr $string, $part{$_}, 1, 1 for @parts;
    my %back = reverse %part;
    my $store = 1;
    for my $seen (keys %store) {
        my $result = "$seen" | "$string";

        if ($result =~ /^3+$/  # Same as old.
            || $result !~ /1/  # Contained in old.
        ) {
            $store = 0;

        } elsif ($result !~ /2/) {  # Contains old.
            delete $store{$seen};
        }
    }
    undef $store{$string =~ tr/1/2/r} if $store;
}

say 'Kept: ';
my %back = reverse %part;
for my $stored (keys %store) {
    say join '|',
        map substr($stored, $_, 1) ? $back{$_} : (),
        1 .. length $stored;
}

__DATA__
A001|B002
C003|A001|B002
B002|A001
C003|D004|A001
E005|F006
D004|C003