Hit counter sliding window

Design a hit counter that records hits (each carrying a timestamp in seconds) and can report how many hits occurred in the most recent 300 seconds (a 5-minute window). Implement it with a fixed-size circular buffer of 300 slots, where slot i holds (last_timestamp_seen_in_that_slot, hit_count). Process a list of operations: ['hit', t] records a hit at timestamp t and returns -1 (no output value), and ['getHits', t] returns the number of hits in the window (t-299 .. t] inclusive. Timestamps are positive and non-decreasing across operations. Return the list of results for getHits operations only, in order. There are 1 to 10^4 operations.