tweet counts per frequency

tweet counts per frequency

这个复杂度我还不会算。

c++的标准库用的还是不熟练，map是有自动排序的，所以这里很方便。

class TweetCounts {
public:
    TweetCounts() {

    }
    void recordTweet(string tweetName, int time) {
        record[tweetName][time] ++;
    }

    vector<int> getTweetCountsPerFrequency(string freq, string tweetName, int startTime, int endTime) {
        int f = 60;
        if (freq == "hour") f *= 60;
        if (freq == "day") f *= 60 * 24;
        vector<int> ans(0);
        int t = startTime;
        while (t <= endTime) {
            auto low = record[tweetName].lower_bound(t);
            auto up = record[tweetName].upper_bound(min(t+f-1, endTime));
            int cnt = 0;
            for (auto it = low; it != up; it++) 
                cnt += it->second;
            ans.push_back(cnt);
            t += f;
        }
        return ans;
    }
private:
    unordered_map<string, map<int, int>> record;
};

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