sub contains { # return true if $_[0] is contained in $_[1]
  my ($s, $t) = @_;
  for (split('', $s)) {
    return 0 unless ($t =~ s/$_//);
  }
  1;
}
print contains("dog", "good"), "\n"; # -> 1
print contains("food", "fodder"), "\n"; # -> 0