n = input()
list1 = list(map(int,input().split(' ')))
workcount = [0]
money = [0]
for i in list1:
if i==0:
for j in range(len(workcount)):
workcount[j]=0
elif i==1:
for j in range(len(workcount)):
workcount[j]+=1
money[j]+=workcount[j]
elif i==2:
money = money*2
# 50%加班
for j in range(len(workcount)):
workcount[j]+=1
money[j]+=workcount[j]
# 50%不加班
while len(workcount) != len(money):
workcount.append(0)
avg = sum(money)/len(money)
print(avg)
我把最后求平均值的/换成//就36%了。。。。然后跑去第二题想不出来回来想改第一题思路断了 没时间了
#360笔试##360公司##笔试题目#
