My solution https://codeforces.me/contest/1973/submission/381965363 wrongly passes al the test cases for the problem when for:

$$$n = 10$$$

$$$k = 3$$$

$$$a = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1]$$$

it asks $$$29 \gt 2n$$$ total queries.