Codefights

A way to improve your programming skills.

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Video Part

Description

You have been watching a video for some time. Knowing the total video duration find out what portion of the video you have already watched.

Example

For part = "02:20:00" and total = "07:00:00", the output should be videoPart(part, total) = [1, 3].

You have watched 1 / 3 of the whole video.

Input/Output

  • [execution time limit] 4 seconds (js)

  • [input] string part

    A string of the following format "hh:mm:ss" representing the time you have been watching the video.

  • [input] string total

    A string of the following format "hh:mm:ss" representing the total video duration.

  • [output] array.integer

    • An array of the following format [a, b] (where a / b is a reduced fraction).

    Note (reduced fraction): We call a fraction reduced if its numerator and denominator are relatively prime.

    Note (relatively prime): Two integers are said to be relatively prime (or coprime) if the only positive integer that evenly divides both of them is 1.

[JavaScript (ES6)] Syntax Tips

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// Prints help message to the console
// Returns a string
function helloWorld(name) {
console.log("This prints to the console when you Run Tests");
return "Hello, " + name;
}

Solution

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function videoPart(part, total) {
  part = part.split(":").map(Number);
  total = total.split(":").map(Number);
  var partSecs = part[0] * 3600 + part[1] * 60 + part[2];
  var totalSecs = total[0] * 3600 + total[1] * 60 + total[2];
  var mcd = gcd(partSecs, totalSecs);
  return [partSecs / mcd, totalSecs / mcd];
}

function gcd(a, b) {
  if (!b) {
    return a;
  }

  return gcd(b, a % b);
}