#!/usr/bin/perl
use strict;
use warnings;

my @data = (
    '$?/1dlw&', '*%1sdh^?', '@/!1dlw\\/',
    '$£1cgi*&', '?@1sdh%&', '~#1xnf$%'
);

my @patterns = qw/1dlw 1sdh 1cgi 1xnf/;
my $re = join "|", map quotemeta, @patterns;

my %seen;
/($re)/ and $seen{$1}++ for (@data);

my $unique = join "|", map quotemeta, grep { $seen{$_} == 1 } @patterns;
my @unique = grep { /$unique/ } @data;