#!/usr/bin/perl

my @words = ('aa', 'as', 'es', 'is', 'os', 'sh', 'si', 'so');
print "WORDS: @words\n";

print "----------------------------\n";

my $regex = ".?a?";
print "Matches for regex pattern : $regex\n\n";

foreach (@words) {
	if(join('', sort split //, $_) =~ /^$regex$/) {
		print "$_\n";
	}
}

print "----------------------------\n";

my $regex = "a?.?";
print "Matches for regex pattern : $regex\n\n";

foreach (@words) {
	if(join('', sort split //, $_) =~ /^$regex$/) {
		print "$_\n";
	}
}

print "----------------------------\n";

$regex = "s?.?";
print "Matches for regex pattern : $regex\n\n";

foreach (@words) {
	if(join('', sort split //, $_) =~ /^$regex$/) {
		print "$_\n";
	}
}


print "----------------------------\n";

$regex = ".?s?";
print "Matches for regex pattern : $regex\n\n";


foreach (@words) {
	if(join('', sort split //, $_) =~ /^$regex$/) {
		print "$_\n";
	}
}


print "----------------------------\n";