Codeforces Round 848 (Div. 2) |
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Finished |
You are given an array of $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$. The integers are either $$$1$$$ or $$$-1$$$. You have to perform the following operation exactly once on the array $$$a$$$:
What is the maximum possible value of $$$a_1 + a_2 + \ldots + a_n$$$ after applying the above operation?
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 500$$$). Description of the test cases follows.
The first line of each test case contains a single integer $$$n$$$ ($$$2 \le n \le 10^5$$$), the length of the array $$$a$$$.
The next line contains $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$a_i = 1$$$ or $$$a_i = -1$$$).
The sum of $$$n$$$ over all cases doesn't exceed $$$10^5$$$.
For each test case, print the maximum possible sum of the array $$$a$$$ you can get in a separate line.
45-1 1 1 -1 -151 1 -1 -1 -121 141 -1 -1 1
3 3 -2 4
In the first case, we can choose index $$$4$$$ and flip the signs of $$$a_4$$$ and $$$a_5$$$. After this operation, the sum will be $$$-1+1+1+1+1 = 3$$$. We can't make the sum larger than this.
In the third case, the only option is to choose the index $$$1$$$.
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