JS Solution, Date function
\nuse ceil to get the valid start time.\n\nvar numberOfRounds = function(startTime, finishTime) {\n    var s = new Date(`2020-01-01T${startTime}:00Z`);\n    var
\nuse ceil to get the valid start time.\n```\nvar numberOfRounds = function(startTime, finishTime) {\n    var s = new Date(`2020-01-01T${startTime}:00Z`);\n    var e;\n    if(finishTime < startTime)\n        e = new Date(`2020-01-02T${finishTime}:00Z`);\n    else\n        e = new Date(`2020-01-01T${finishTime}:00Z`);\n    var st = Math.ceil(s.getTime() / 15 / 60000) * 15 * 60000;\n    return Math.floor((e.getTime() - st) / (15 * 60000));\n};\n```
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