输出格式要求：计算日历列上事件重叠数量的教程

class Event:
    def __init__(self, hour_start, hour_end):
        self.hour_start = hour_start
        self.hour_end = hour_end

def is_overlap(event_a, event_b):
    """
    判断两个事件是否重叠。

    Args:
        event_a: 第一个事件对象。
        event_b: 第二个事件对象。

    Returns:
        如果两个事件重叠，则返回 True，否则返回 False。
    """
    return (event_a.hour_start >= event_b.hour_start and event_a.hour_start <= event_b.hour_end) or \
           (event_a.hour_end >= event_b.hour_start and event_a.hour_end <= event_b.hour_end)

# 示例
event1 = Event(8, 10)
event2 = Event(9, 11)
event3 = Event(12, 14)

print(f"Event1 and Event2 overlap: {is_overlap(event1, event2)}") # 输出: Event1 and Event2 overlap: True
print(f"Event1 and Event3 overlap: {is_overlap(event1, event3)}") # 输出: Event1 and Event3 overlap: False

def count_overlapping_events(events):
    """
    计算事件列表中重叠事件的数量。

    Args:
        events: 事件列表。

    Returns:
        重叠事件的数量。
    """
    count = 0
    n = len(events)
    for i in range(n):
        for j in range(i + 1, n): # 避免重复比较，只比较 i 之后的事件
            if is_overlap(events[i], events[j]):
                count += 1
    return count

# 示例
events = [
    Event(8, 10),
    Event(9, 11),
    Event(12, 14),
    Event(13, 15)
]

overlapping_count = count_overlapping_events(events)
print(f"Number of overlapping events: {overlapping_count}") # 输出: Number of overlapping events: 2