P25221 [AtCoder] Sum
普及+
题目描述

Problem Statement

You are given $non-zero integers x_1, \ldots, x_N.$ Find the minimum and maximum values of $\dfrac{x_i+x_j+x_k}{x_ix_jx_k}$ for integers i, j, k such that $1\leq i < j < k\leq N$.

Input

The input is given from Standard Input in the following format:
N
$x_1 \ldots x_N$

Output

Print the minimum value of $\dfrac{x_i+x_j+x_k}{x_ix_jx_k}$ in the first line and the maximum value in the second line.
Your output will be considered correct when the absolute or relative error is at most 10^{-12}.

Constraints

  • $3\leq N\leq 2\times 10^5$
  • -$10^6\leq x_i \leq 10^6$
  • $x_i\neq 0$

Sample Input 1

4
-2 -4 4 5

Sample Output 1

-0.175000000000000
-0.025000000000000

$\dfrac{x_i+x_j+x_k}{x_ix_jx_k}$ can take the following four values.

  • (i,j,k) = (1,2,3): $\dfrac{(-2) + (-4) + 4}{(-2)\cdot (-4)\cdot 4} = -\dfrac{1}{16}$.
  • (i,j,k) = (1,2,4): $\dfrac{(-2) + (-4) + 5}{(-2)\cdot (-4)\cdot 5} = -\dfrac{1}{40}$.
  • (i,j,k) = (1,3,4): $\dfrac{(-2) + 4 + 5}{(-2)\cdot 4\cdot 5} = -\dfrac{7}{40}$.
  • (i,j,k) = (2,3,4): $\dfrac{(-4) + 4 + 5}{(-4)\cdot 4\cdot 5} = -\dfrac{1}{16}$.

Among them, the minimum is -$\dfrac{7}{40}$, and the maximum is -$\dfrac{1}{40}$.

Sample Input 2

4
1 1 1 1

Sample Output 2

3.000000000000000
3.000000000000000

Sample Input 3

5
1 2 3 4 5

Sample Output 3

0.200000000000000
1.000000000000000

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
4 -2 -4 4 5
样例输出
-0.175000000000000 -0.025000000000000