第三课：分支应用 🎮

import random

# 📝 准备游戏选项
choices = ["石头", "剪刀", "布"]

while True:
    print("🎮 欢迎来到石头剪刀布游戏！")
    select = int(input("是否开始游戏？(0->退出, 1->开始): "))
    
    if select == 0:
        print("👋 再见！感谢游戏！")
        break
    elif select == 1:
        while True:
            # 🎯 玩家选择
            player = input("请选择(石头/剪刀/布): ")
            
            # ✅ 修正后的判断条件
            if player not in choices:
                print("🙈 输入错误，请重新选择！")
                continue
            
            # 🤖 电脑随机选择
            computer = random.choice(choices)
            
            # 📢 显示选择结果
            print(f"👤 玩家选择：{player}")
            print(f"🤖 电脑选择：{computer}")
            
            # 🏆 判断胜负
            if player == computer:
                print("🤝 平局！再来一局吧！")
            elif (player == "石头" and computer == "剪刀") or \
                 (player == "剪刀" and computer == "布") or \
                 (player == "布" and computer == "石头"):
                print("🎉 玩家胜利！太棒了！")
            else:
                print("😅 电脑胜利！继续努力！")
            
            # 问是否继续
            again = input("继续游戏吗？(y/n): ")
            if again.lower() != 'y':
                break
    else:
        print("🙉 请输入0或1哦！")

# 📝 梯形面积计算程序
# 一行输入三个数，用空格分开
a, b, h = input().split()

# 🔄 把字符串转换成整数
a = int(a)
b = int(b)  
h = int(h)

# 🧮 计算面积：(上底 + 下底) × 高 ÷ 2
area = (a + b) * h / 2

# 📋 输出结果，保留1位小数
print("%.1f" % area)

# 🏫 教室数量计算程序
# 输入总人数和每个教室容量
total_students, room_capacity = input().split()
total_students = int(total_students)
room_capacity = int(room_capacity)

# 🧮 计算需要几个教室
if total_students % room_capacity == 0:
    # 整除情况：刚好坐满
    rooms_needed = total_students // room_capacity
else:
    # 有余数：需要多一个教室
    rooms_needed = total_students // room_capacity + 1

print(rooms_needed)

# 📅 闰年判断程序
year = int(input())

# 🧮 闰年判断逻辑
# 方法1：分两种情况判断
if year % 400 == 0:
    print("yes")  # 能被400整除 → 闰年
elif year % 100 == 0:
    print("no")   # 能被100整除但不能被400整除 → 平年
elif year % 4 == 0:
    print("yes")  # 能被4整除但不能被100整除 → 闰年  
else:
    print("no")   # 其他情况 → 平年

# 方法2：一行搞定（更简洁！）
# if (year % 4 == 0 and year % 100 != 0) or (year % 400 == 0):
#     print("yes")
# else:
#     print("no")