TWC280

Challenge Link

Task1

We basically count the number of occurrences of characters and return the duplicated one. We can do this more compactly with regexp:

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

sub twice_appearance{
  reverse($_[0]) =~ /.*(.).*?\1/
}

printf "%s\n",twice_appearance('acbddbca');
printf "%s\n",twice_appearance('abccd');
printf "%s\n",twice_appearance('abcdabbb');

Task2

We count the number of asterisks of the wanted portions of the string:

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

sub count_asterisks{
  my $str = $_[0] =~ s/\|[^\|]*\|//gmixr;
  $_ = () = $str =~ /(\*)/gmix;
}

printf "%d\n",count_asterisks('p|*e*rl|w**e|*ekly|');
printf "%d\n",count_asterisks('perl');
printf "%d\n",count_asterisks('th|ewe|e**|k|l***ych|alleng|e');