#3个瓶盖可以兑换一瓶饮料，买了n瓶饮料，一共可以喝到多少瓶
def get_drink(n):
    total = 0
    left = 0
    while n>=3:
        total +=n
        left += n%3
        if left>=3:
            total +=left//3
            left = left%3
        n = n//3
    return total
t = get_drink(100)
print(t)
也可以写成:

def get_drink(n):
    total = 0
    left = 0
    while n>=3:
        total +=n
        left += n%3
        if left>=3:
            add, left = divmod(left, 3)
            total+= add
        n = n//3
    return total
t = get_drink(1200)
print(t)
也可以写成

def get_drink(n):
    total = 0
    left = 0
    while n>=3:
        total +=n
        n, left_add = divmod(n, 3)
        left += left_add
        if left>=3:
            total_add, left = divmod(left, 3)
            total+= total_add
    return total
print(get_drink(100))

注意：

print(5//4)
#结果为1，取到商的整数
print(5/4)
#结果为1.25
a, b = divmod(5, 4)
print(a, b)
#结果为1，1，divmod(a，b)可以取到商的整数