date-overlap.md

Exercise

You have time-stamps (mentioned as integers), which represents phone call begin and end to booking.com call center. find the number of overlaps in calls that suggests to add more call center agents.

Answer

let calls = [
  {
    start: new Date(
      "Mon Feb 03 2020 17:42:04 GMT+0100 (Central European Standard Time)"
    ),
    end: new Date(
      "Mon Feb 03 2020 18:42:04 GMT+0100 (Central European Standard Time)"
    )
  },
  {
    start: new Date(
      "Mon Feb 03 2020 17:45:04 GMT+0100 (Central European Standard Time)"
    ),
    end: new Date(
      "Mon Feb 03 2020 22:42:04 GMT+0100 (Central European Standard Time)"
    )
  },
  {
    start: new Date(
      "Mon Feb 03 2020 17:45:04 GMT+0100 (Central European Standard Time)"
    ),
    end: new Date(
      "Mon Feb 03 2020 19:42:04 GMT+0100 (Central European Standard Time)"
    )
  },
  {
    start: new Date(
      "Mon Feb 03 2020 21:45:04 GMT+0100 (Central European Standard Time)"
    ),
    end: new Date(
      "Mon Feb 03 2020 22:42:04 GMT+0100 (Central European Standard Time)"
    )
  },
  {
    start: new Date(
      "Mon Feb 03 2020 05:45:04 GMT+0100 (Central European Standard Time)"
    ),
    end: new Date(
      "Mon Feb 03 2020 07:42:04 GMT+0100 (Central European Standard Time)"
    )
  }
];

function dateRangeOverlaps(a_start, a_end, b_start, b_end) {
  if (a_start <= b_start && b_start <= a_end) return true; // b starts in a
  if (a_start <= b_end && b_end <= a_end) return true; // b ends in a
  if (b_start < a_start && a_end < b_end) return true; // a in b
  return false;
}

let overlap = calls => {
  const callsInt = calls.map(({ start, end, id }) => ({
    start: start.getTime(),
    end: end.getTime()
  }));

  return callsInt.map(({ start, end, id }) => {
    const overlaps =
      callsInt.filter(otherCall =>
        dateRangeOverlaps(start, end, otherCall.start, otherCall.end)
      ).length - 1;

    return {
      start: new Date(start),
      end: new Date(end),
      overlaps
    };
  });
};

console.log(overlap(calls));