AtCoder Regular Contest 158
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Problem Statement
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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 $1\leq i < j < k\leq N$.
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Constraints
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$3\leq N\leq 2\times 10^5$$-10^6\leq x_i \leq 10^6$$x_i\neq 0$
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Input
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The input is given from Standard Input in the following format:
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N
x_1 \ldots x_N
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Output
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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.
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Your output will be considered correct when the absolute or relative error is at most $10^{-12}$.
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样例
Input #1
4
-2 -4 4 5
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 $-\dfrac{1}{40}$.
Input #2
4
1 1 1 1
Output #2
3.000000000000000
3.000000000000000
Input #3
5
1 2 3 4 5
Output #3
0.200000000000000
1.000000000000000
题目信息
题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。