Number of Recent Calls Solutions in C++

// Source : https://leetcode.com/problems/number-of-recent-calls/
// Author : Hao Chen
// Date   : 2020-07-26



class RecentCounter {
public:
    RecentCounter() {

    }

    int ping(int t) {
        req.push_back(t);
        return req.size() - binary_search(t-3000);
    }
private:
    vector<int> req;
    int binary_search(int x) {
        int low=0, high=req.size()-1;
        while(low < high) {
            int mid = low + (high -low) / 2;
            if ( req[mid] == x ) return mid;
            if ( req[mid] < x ) low = mid + 1;
            else high = mid - 1;
        }
        cout << "x="  << x << "\tlow=" << low << endl;
        return x > req[low] ? low+1 : low ;
    }
};

/**
 * Your RecentCounter object will be instantiated and called as such:
 * RecentCounter* obj = new RecentCounter();
 * int param_1 = obj->ping(t);
 */

/// Source : https://leetcode.com/problems/number-of-recent-calls/
/// Author : liuyubobobo
/// Time   : 2018-11-03

#include <iostream>
#include <queue>

using namespace std;


/// Using a Queue
/// Time Complexity: O(query)
/// Space Complexity: O(3000)
class RecentCounter {

private:
    queue<int> q;
public:
    RecentCounter() { }

    int ping(int t) {
        q.push(t);
        while(t - 3000 > q.front())
            q.pop();
        return q.size();
    }
};


int main() {

    return 0;
}