C. Electrificationtime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputAt first, there was a legend related to the name of the problem, but now it's just a formal statement.You are given n points a_1, a_2, \dots, a_n on the OX axis. Now you are asked to find such an integer point x on OX axis that f_k(x) is minimal possible.The function f_k(x) can be described in the following way:   form a list of distances d_1, d_2, \dots, d_n where d_i = |a_i - x| (distance between a_i and x);  sort list d in non-descending order;  take d_{k + 1} as a result. If there are multiple optimal answers you can print any of them.InputThe first line contains single integer T ( 1 \le T \le 2 \cdot 10^5) — number of queries. Next 2 \cdot T lines contain descriptions of queries. All queries are independent. The first line of each query contains two integers n, k (1 \le n \le 2 \cdot 10^5, 0 \le k < n) — the number of points and constant k.The second line contains n integers a_1, a_2, \dots, a_n (1 \le a_1 < a_2 < \dots < a_n \le 10^9) — points in ascending order.It's guaranteed that \sum{n} doesn't exceed 2 \cdot 10^5.OutputPrint T integers — corresponding points x which have minimal possible value of f_k(x). If there are multiple answers you can print any of them.ExampleInput
3
3 2
1 2 5
2 1
1 1000000000
1 0
4
Output
3
500000000
4

3
3 2
1 2 5
2 1
1 1000000000
1 0
4

3 500000000 4 
['binary search', 'brute force', 'greedy', '*1600']