Easy Solution in C++
\nclass Solution {\npublic:\n    int numberOfRounds(string startTime, string finishTime) {\n        int h1 = stoi(startTime.substr(0,2));\n        int h2 = stoi
```\nclass Solution {\npublic:\n    int numberOfRounds(string startTime, string finishTime) {\n        int h1 = stoi(startTime.substr(0,2));\n        int h2 = stoi(finishTime.substr(0,2));\n        int m1 = stoi(startTime.substr(3));\n        int m2 = stoi(finishTime.substr(3));\n        if(h2*60+m2<h1*60+m1) h2+=24;\n        return h2-h1>=1 ? (h2-h1-1)*4 + rounds(m1, 60) + rounds(0,m2) : rounds(m1,m2);\n    }\n    int rounds(int s, int e){\n        int slot[] = {0,15,30,45,60};\n        int count=0;\n        for(int i=0;i<4;i++){\n            if(s<=slot[i] && e>=slot[i+1]) count++;\n        }\n        return count;\n    }\n};\n```
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