Today, finally for the first time in the history, I got a test case to hack the Problem D[problem:2155D]. But after the contest ended :(

The test case is actually easy

n = 40, a = 4 and the active positions as [1 14 27 40] It should find under 400 operations, but everyone who wrote the code with checking with iterating on the gap between the batteries will get the result in approx 403-404 queries.

One day, I'll also hack, today I got the motivation.