(C++ 練習) 933. Number of Recent Calls

題目 :

Write a class RecentCounter to count recent requests.

It has only one method: ping(int t), where t represents some time in milliseconds.

Return the number of pings that have been made from 3000 milliseconds ago until now.

Any ping with time in [t - 3000, t] will count, including the current ping.

It is guaranteed that every call to ping uses a strictly larger value of t than before.

大意 :

這個題目只有一個method : ping(int t), 而 t 代表的是 3000ms 之前到現在的呼叫次數.

題目有個需求, 就是 tn 必須大於前一個的 tn-1

class RecentCounter {
public:
    RecentCounter() {}

    int ping(int t) {
        while (!q.empty() && t - q.front() > 3000) q.pop();
        q.push(t);
        return q.size();
    }
private:
    queue<int> q;
};