2933. High-Access Employees

You are given a 2D 0-indexed array of strings, access_times, with size n. For each i where 0 <= i <= n - 1, access_times[i][0] represents the name of an employee, and access_times[i][1] represents the access time of that employee. All entries in access_times are within the same day.

The access time is represented as four digits using a 24-hour time format, for example, "0800" or "2250".

An employee is said to be high-access if he has accessed the system three or more times within a one-hour period.

Times with exactly one hour of difference are not considered part of the same one-hour period. For example, "0815" and "0915" are not part of the same one-hour period.

Access times at the start and end of the day are not counted within the same one-hour period. For example, "0005" and "2350" are not part of the same one-hour period.

Return a list that contains the names of high-access employees with any order you want.

class Solution {
    bool ok(vector<string>& A) {
        vector<int> time;
        for(auto& s : A) {
            int t = (s[0] - '0') * 10 + s[1] - '0';
            t *= 60;
            t += (s[2] - '0') * 10 + s[3] - '0';
            time.push_back(t);
        }
        sort(begin(time), end(time));
        for(int i = 0, j = 0; j < time.size(); i++) {
            while(j < time.size() and time[i] + 60 > time[j]) j += 1;
            if(j - i >= 3) return true;
        }
        return false;
    }
public:
    vector<string> findHighAccessEmployees(vector<vector<string>>& access_times) {
        vector<string> res;
        unordered_map<string, vector<string>> mp;
        for(auto& a : access_times) {
            mp[a[0]].push_back(a[1]);
        }
        for(auto& [k,v] : mp) {
            if(ok(v)) res.push_back(k);
        }
        
        return res;
    }
};