Sherlock and numbers - HackerEarth Problem Solution

Sherlock and numbers - HackerEarth Problem Solution :
          Watson gives to sherlock a bag of numbers [1,2,3,....N] and he removes k numbers A1, A2,....,Ak from the bag. He now asks sherlock to find the pth smallest number in the bag.

Input:

2
4 1 2
1
5 2 4
1 3

Output:

3
-1

Test case 1:
                   Remaining Numbers are [2,3,4]. 3 is the 2nd smallest remaining numbers
                   Remaining Numbers are [2,4,5]. 4th smallest number doesn't exist.

PHP Implementation:

<?php fscanf(STDIN,"%d",$T); $arr=array(); $arrb=array(); while($T>0) { fscanf(STDIN,"%d %d %d",$N,$K,$P); $input=trim(fgets(STDIN)); $arr=explode(" ",$input); foreach($arr as &$number) { $number=(int)$number; } $i=0; $x=1; $l=0; while($l<$K) { if($x==$arr[$l]) { $l++; $x++; } else { $arrb[$i]=$x; $x++; $i++; } } while($i<($N-$K)) { $arrb[$i]=$x; $x++; $i++; } $i--; if($P<=$i) fprintf(STDOUT,"%d\n",$arrb[$P-1]); else fprintf(STDOUT,"%d\n",-1); $T--; }