public class HitCounter {
    List<Integer> data;
    /** Initialize your data structure here. */
    public HitCounter() {
        data = new ArrayList();
        data.add(Integer.MIN_VALUE);
        data.add(Integer.MAX_VALUE);
    }

    /** Record a hit.
        @param timestamp - The current timestamp (in seconds granularity). */
    public void hit(int timestamp) {
        data.set(data.size() - 1, timestamp);
        data.add(Integer.MAX_VALUE);
    }

    /** Return the number of hits in the past 5 minutes.
        @param timestamp - The current timestamp (in seconds granularity). */
    public int getHits(int timestamp) {
        return getHitsBelow(timestamp + 1) - getHitsBelow(timestamp - 300 + 1);
    }

    private int getHitsBelow(int timestamp) {
        int lo = 0;
        int hi = data.size();
        while(lo < hi) {
            int mid = lo + (hi - lo) / 2;
            if(data.get(mid) < timestamp && data.get(mid + 1) >= timestamp) {
                return mid;
            }
            if(data.get(mid) >= timestamp) {
                hi = mid;
            } else {
                lo = mid + 1;
            }
        }
        return hi;
    }
}

/**
 * Your HitCounter object will be instantiated and called as such:
 * HitCounter obj = new HitCounter();
 * obj.hit(timestamp);
 * int param_2 = obj.getHits(timestamp);
 */