find_pockets_of_free_time.py

#!/usr/bin/env python3

e_o_d = 23

def find_pockets_of_free_time(meeting_times):
    day = [False] * 24
    available_times = []

    for start, finish in meeting_times:
        if start > finish:  finish = e_o_d
        if finish == e_o_d: finish += 1

        day[start:finish] = [True] * len(range(start, finish))

    s = 0
    for hour, busy in enumerate(day):
        if busy:
            if not day[s]:
                available_times.append((s, hour))
            s = hour + 1

    if not day[-1]:
        available_times.append((s, e_o_d))

    return available_times