# 保证活动是按结束时间排好序的
activities = [(1, 4), (3, 5), (0, 6), (5, 7), (3, 9), (5, 9), (6, 10), (8, 11), (8, 12), (2, 14), (12, 16)]
activities.sort(key=lambda x:x[1])


def activity_selection(a):
    """活动排程问题"""

    res = [a[0]]

    for i in range(1, len(a)):
        if a[i][0] >= res[-1][1]:
            res.append(a[i])

    return res