Codeforces Round 884 (Div. 1 + Div. 2)
C
Particles
Codeforces
1300
原题
← BD →
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You have discovered $n$ mysterious particles on a line with integer charges of $c_1,\dots,c_n$. You have a device that allows you to perform the following operation:

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  • Choose a particle and remove it from the line. The remaining particles will shift to fill in the gap that is created. If there were particles with charges $x$ and $y$ directly to the left and right of the removed particle, they combine into a single particle of charge $x+y$.
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For example, if the line of particles had charges of $[-3,1,4,-1,5,-9]$, performing the operation on the $4$th particle will transform the line into $[-3,1,9,-9]$.

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image

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If we then use the device on the $1$st particle in this new line, the line will turn into $[1,9,-9]$.

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You will perform operations until there is only one particle left. What is the maximum charge of this remaining particle that you can obtain?

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Input

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Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.

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The first line of each test case contains a single integer $n$ ($1 \le n \le 2 \cdot 10^5$).

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The second line of each test case contains $n$ integers $c_1,\dots,c_n$ ($-10^9 \le c_i \le 10^9$).

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It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$.

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Output

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For each test case, output one integer, the maximum charge of the remaining particle.

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Note

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In the first test case, the best strategy is to use the device on the $4$th particle, then on the $1$st particle (as described in the statement), and finally use the device on the new $3$rd particle followed by the $1$st particle.

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In the second test case, the best strategy is to use the device on the $4$th particle to transform the line into $[998244353,998244353,1996488706]$, then on the $2$nd particle to transform the line into $[2994733059]$. Be wary of integer overflow.

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In the third test case, there is only one particle, so no operations can be performed.

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样例

Input #1
3
6
-3 1 4 -1 5 -9
5
998244353 998244353 998244353 998244353 998244353
1
-2718
Output #1
9
2994733059
-2718
InputCopy OutputCopy
题目信息
题号
1844C
时间限制
1 s
内存限制
256 MB
标签
动态规划
贪心
模拟
数学

题面与样例版权归 Codeforces 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。