题解 | 记负均正

def fun():
    n = int(input())
    m = list(map(int,input().split()))
    neg_num = 0
    pos_num = []
    for i in m:
        if i < 0:
            neg_num += 1
        if i > 0:
            pos_num.append(i)
    if len(pos_num) == 0:
        mean_value = 0
    else:
        mean_value = sum(pos_num)/len(pos_num)
    return neg_num, "{:.1f}".format(mean_value)

neg_num, mean_value = fun()
print(neg_num, mean_value)