Assign the Assignments

Ninja and his friend are working on an assignment that contains ‘N’ tasks. Each task has a complexity ‘C[i]’.

Ninja wants to assign ‘B’ number of tasks to his friend and ‘A’ number of tasks to himself. Given that he can only assign tasks with complexity greater than or equal to 'X' to himself and tasks with complexity less than 'X' to his friend.

So help Ninja to find how many ways are there to choose ‘X’ such that Ninja gets ‘A’ and his friend gets ‘B’ number of tasks.

Note :

The complexity of each task is pairwise distinct.

For example :

N a b
5 3 2
C: 5 19 2 62 1
Here ‘X’ can be 2,3,4 as 3 tasks have greater complexity that will be assigned to Ninja and the remaining two will be assigned to NInja’s friend.
So the answer is 3.

Input Format :

The first line contains a single integer ‘T’ representing the number of test cases. Then test cases follow:

The first line contains three integers ‘N’, ‘A’, and ‘B’ representing the total number of tasks, number of tasks that will ninja solve, and the number of tasks that ninja’s friend will solve.

The second line contains  ‘N’ space-separated elements denoting the complexity of each task.

Output Format :

For each test case, return an integer denoting the number of ways to choose ‘X’ as described in the problem.

Note :

You don’t need to print anything. It has already been taken care of. Just implement the given function.

Constraints :

1 <= T <= 5
2 <= N <= 10^5
1 <= A,B <= N
1 <= C[i] <= 10^9    

Time Limit: 1 sec