パーティにいく時間

    sched = [(6, 8), (6, 12), (6, 7), (7, 8),
             (7, 10), (8, 9), (8,10), (9,12),
             (9,10),(10, 11), (10, 11),(10, 12), (11,12)]

    def bestTimeToParty(schedule):
        start = schedule[0][0]
        end = schedule[0][1]
        for c in schedule:
            start = min(c[0],start)
            end = max(c[1], end)
        count = celebrityDensity(schedule, start, end)
        maxcount = 0
        for i in range(start, end + 1):
            if count[i] > maxcount:
                maxcount = count[i]
                time = i

        print('Best time to attend the paty is at', time,'o\'clock',
                ':', maxcount, 'celebrities will be attending!')

    def celebrityDensity(sched, start, end):
        count = [0] * (end +1)
        for i in range(start, end + 1):
            count[i] = 0
            for c in  sched:
                if c[0] <= i and c[1] > i:
                    count[i] += 1
        return  count

作成した関数を実行する
    bestTimeToParty(sched)

結果は　
Best time to attend the paty is at 9 o'clock : 5 celebrities will be attending!