#!/usr/bin/perl -w

use strict;
my $str;
my @test = ("0000","0001","0010","0011",
	    "0100","0101","0110","0111",
	    "1000","1001","1010","1011",
	    "1100","1101","1110","1111");
my @accepted = (0,8,10,12,15);

for my $t (@test) {
  print "Input: $t\tTested: ";
  print "[" . parsebin($t) . "] " ;
  print validinput($t,\@accepted);
  print "\n";
}

sub validinput {
  my $in = shift;
  my $r = shift;
  return 1 if xinset(parsebin($in),$r);
  return 0;
}

sub xinset {
  my $x = shift;
  my $set = shift;
  #print "X $x SET" . join(" / ",@$set). "\n";
  for my $y (@$set) {
    return 1 if $x == $y;
  }
  return 0;
}

sub parsebin {
  # parse a string of ones and zeroes
  my $str = shift;
  my $total = 0;
  my $power = 0;
  for my $i (1..length($str)) {
    $total += 2 ** $power if substr($str,-1 * $i,1);
    $power++;
  }

  return $total;
}