题解 | #学分绩点#

# 读取输入
n = int(input())
credits = list(map(int, input().split()))
scores = list(map(int, input().split()))

# 计算总评绩点
total_credit_point = 0
total_credit = sum(credits)
for i in range(n):
    if 90 <= scores[i] <= 100:
        point = 4.0
    elif 85 <= scores[i] <= 89:
        point = 3.7
    elif 82 <= scores[i] <= 84:
        point = 3.3
    elif 78 <= scores[i] <= 81:
        point = 3.0
    elif 75 <= scores[i] <= 77:
        point = 2.7
    elif 72 <= scores[i] <= 74:
        point = 2.3
    elif 68 <= scores[i] <= 71:
        point = 2.0
    elif 64 <= scores[i] <= 67:
        point = 1.5
    elif 60 <= scores[i] <= 63:
        point = 1.0
    else:
        point = 0
    total_credit_point += point * credits[i]

# 输出总评绩点
GPA = total_credit_point / total_credit
print("{:.2f}".format(GPA))