MOST efficient method, beat 100%
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```cpp []\n#include <iostream>\n#include <string>\n\nclass Solution {\npublic:\n    int numberOfRounds(string loginTime, string logoutTime) {\n        int loginMinutes = timeToMinutes(loginTime);\n        int logoutMinutes = timeToMinutes(logoutTime);\n\n        if(logoutMinutes<loginMinutes){\n            logoutMinutes += 24 * 60;\n        }\n        int firstRound = ((loginMinutes+14)/15)*15;\n        int lastRound =  (logoutMinutes / 15) * 15;\n\n        if(firstRound>lastRound) return 0;\n        \n        return (lastRound - firstRound)/15;\n    }\n    private:\n    int timeToMinutes(const string&time){\n        int hours = stoi(time.substr(0,2));\n        int minutes = stoi(time.substr(3,2));\n        return hours * 60 + minutes;\n    }\n};\n```
['C++']