question 139 Built-ins & Sorting · hard

The busiest departure hour

Airport operations staff the security lanes for the busiest hour of the day. Given the scheduled departure times, find the hour with the most departures. If two hours are equally busy, staff the earlier one first. A day with no departures has no busiest hour.

Functionbusiest_hour(departures)

departuresa list of 24-hour times as text, "HH:MM" (always two digits each)

Returnsthe busiest hour as a whole number from 0 to 23, or None for no departures

Tiesequally busy hours → the earliest hour

Examples

callbusiest_hour(['05:00', '06:15', '05:10', '06:40', '05:55', '17:20', '06:05'])returns5

callbusiest_hour(['13:30'])returns13

callbusiest_hour([])returnsNone