1
var TweetCounts = function () {
2
  this.map = new Map();
3
};
4

5
TweetCounts.prototype.recordTweet = function (tweetName, time) {
6
  if (!this.map.has(tweetName)) this.map.set(tweetName, []);
7
  this.map.get(tweetName).push(time);
8
};
9

10
TweetCounts.prototype.getTweetCountsPerFrequency = function (
11
  freq,
12
  tweetName,
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  startTime,
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  endTime
15
) {
16
  if (!this.map.has(tweetName)) return [];
17

18
  const tweets = this.map.get(tweetName);
19
  const buckets = createBuckets(freq, startTime, endTime);
20

21
  for (let i = 0; i < tweets.length; i++) {
22
    const tweetTime = tweets[i];
23

24
    let left = 0;
25
    let right = buckets.length - 1;
26

27
    while (left <= right) {
28
      const mid = (left + right) >> 1;
29
      const [startTime, endTime, count] = buckets[mid];
30

31
      if (startTime <= tweetTime && tweetTime <= endTime) {
32
        buckets[mid][2] = count + 1;
33
        break;
34
      }
35

36
      if (endTime < tweetTime) left = mid + 1;
37
      else right = mid - 1;
38
    }
39
  }
40

41
  const res = [];
42

43
  for (let i = 0; i < buckets.length; i++) {
44
    res.push(buckets[i][2]);
45
  }
46

47
  return res;
48

49
  function createBuckets(freq, startTime, endTime) {
50
    const chunks = { minute: 60, hour: 3600, day: 86400 };
51
    const buckets = [];
52

53
    let start = startTime;
54

55
    while (start <= endTime) {
56
      const end = Math.min(start + chunks[freq] - 1, endTime);
57
      buckets.push([start, end, 0]);
58
      start = end + 1;
59
    }
60

61
    return buckets;
62
  }
63
};