document.write('CHALLENGE Task is here
'); "; #TASK BANNER ENDS #DEBUG MODE 1 $dbg = 0; #INPUT $input_arr = [32,17,113,23,11]; $range = "2-10000"; function is_prime($n,$i=2){ global $dbg; if($dbg) echo "
-->is_prime($n, $i, $dbg )"; if ($n == 2) { $res = true; echo ($dbg)?"--->$res":""; return $res; } if(($n % $i) == 0) { $res = false; echo ($dbg)?"--->$res":""; return $res; } elseif ($i >sqrt($n)) return true; else { $res = is_prime($n, ($i == 2) ?$i+1:$i+2); echo ($dbg)?"--->$res":""; return $res; } } function is_emirp ($n){ return is_prime ($n) && is_prime (strrev($n)) && $n != strrev($n); } function task($i){ $irev = strrev($i); $a = is_prime ($i); $b = is_prime ($irev ); echo "Input: ".$i."
"; echo "Output: "; if ($i == strrev($i)) echo "false(reverse of $i is $i)"; else { if ($a && $b) { echo "true($i and $irev are a prime)
"; } else { echo "false("; echo (!$a)?"$i is not a prime)
":"$i is a prime, but $irev is not a prime)
"; ")"; } } //### } #$input_arr = [32,17,113,23]; #$range = "17-72"; foreach ($input_arr as $i) task($i); echo ""; echo "

Emirp numbers in range [$range]:
"; $rarr = explode("-",$range); $one_printed = 0; for($i = $rarr[0];$i <= $rarr[1];$i++ ){ if (is_emirp($i) ) { echo ($one_printed)?", ":""; echo $i; $one_printed = 1; } } echo ""; ?>