Solution.java

class TweetCounts {
    private Map<String, TreeMap<Integer, Integer>> data = new HashMap<>();

    public TweetCounts() {
    }

    public void recordTweet(String tweetName, int time) {
        data.putIfAbsent(tweetName, new TreeMap<>());
        var tm = data.get(tweetName);
        tm.put(time, tm.getOrDefault(time, 0) + 1);
    }

    public List<Integer> getTweetCountsPerFrequency(
        String freq, String tweetName, int startTime, int endTime) {
        int f = 60;
        if ("hour".equals(freq)) {
            f = 3600;
        } else if ("day".equals(freq)) {
            f = 86400;
        }
        var tm = data.get(tweetName);
        List<Integer> ans = new ArrayList<>();
        for (int i = startTime; i <= endTime; i += f) {
            int s = 0;
            int end = Math.min(i + f, endTime + 1);
            for (int v : tm.subMap(i, end).values()) {
                s += v;
            }
            ans.add(s);
        }
        return ans;
    }
}

/**
 * Your TweetCounts object will be instantiated and called as such:
 * TweetCounts obj = new TweetCounts();
 * obj.recordTweet(tweetName,time);
 * List<Integer> param_2 = obj.getTweetCountsPerFrequency(freq,tweetName,startTime,endTime);
 */