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#18344. 两个海盗 - 2

统计

两个海盗正在瓜分掠夺来的宝藏。一共有 $n$ 件宝藏,其中第 $i$ 件宝藏的价值为 $a_i$ 金币。他们轮流行动,每轮一名海盗会从剩下的宝藏中挑选一件。问题在于,第二个海盗喝醉了,所以他不会做出最优选择,而是每轮等概率随机挑选一件当前可用的宝藏。第一个海盗知道这一点,并且总是做出最优的选择。

求两个海盗各自获得的宝藏价值的期望值。

输入格式

第一行包含一个整数 $n$ ($1 \le n \le 5000$) —— 宝藏的数量。

第二行包含 $n$ 个整数 $a_i$ ($1 \le a_i \le 10^9$) —— 每件宝藏的价值。

输出格式

输出两个浮点数:分别表示第一个海盗和第二个海盗获得的宝藏价值的期望值。

答案的绝对误差或相对误差不应超过 $10^{-9}$。

样例

输入样例 1

2
1 3

输出样例 1

3.000000000000000 1.000000000000000

输入样例 2

3
2 1 4

输出样例 2

5.500000000000000 1.500000000000000

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