#  https://theweeklychallenge.org/blog/perl-weekly-challenge-340/
use v5.12;
use warnings;
use Test::More;

for my $case ('abbaca','azxxzy','aaaaaaaa','aabccba','abcddcba') {

  my $str = $case;
  say "*** Input: $str";
  while ( $str =~s/(\w)\1// ) {
    say "Remove '$&' => '$str'";
  } 
  my $exp = $str;
  say "Expected Output : '$str'";

  $str = $case;
  $str =~ s/((\w)(?1)?\g{-1})//g;
  say "Got Output : '$str'";
  is($exp,$str,"'$case' ->'$str'");

  say "...\n"
}

done_testing()