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: