CF1838A.Blackboard List

普及/提高-

通过率：0%

AC君温馨提醒

该题目为【codeforces】题库的题目，您提交的代码将被提交至codeforces进行远程评测，并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供，我们无法保证该服务的稳定性，若提交后无反应，请等待一段时间后再进行重试。

题目描述

Two integers were written on a blackboard. After that, the following step was carried out $n-2$ times:

Select any two integers on the board, and write the absolute value of their difference on the board.

After this process was complete, the list of $n$ integers was shuffled. You are given the final list. Recover one of the initial two numbers. You do not need to recover the other one.

You are guaranteed that the input can be generated using the above process.

输入格式

The first line of the input contains a single integer $t$ ( $1 \le t \le 100$ ) — the number of test cases. The description of the test cases follows.

The first line of each test case contains a single integer $n$ ( $3 \le n \le 100$ ) — the size of the final list.

The next line of each test case contains $n$ integers $a_1, a_2, \ldots a_n$ ( $-10^9 \le a_i \le 10^9$ ) — the shuffled list of numbers written on the blackboard.

It is guaranteed that the input was generated using the process described above.

输出格式

For each test case, output a single integer $x$ — one of the two initial numbers on the blackboard.

If there are multiple solutions, print any of them.

输入输出样例

输入#1

9
3
9 2 7
3
15 -4 11
4
-9 1 11 -10
5
3 0 0 0 3
7
8 16 8 0 8 16 8
4
0 0 0 0
10
27 1 24 28 2 -1 26 25 28 27
6
600000000 800000000 0 -200000000 1000000000 800000000
3
0 -1000000000 1000000000

输出#1

说明/提示

For the first test case, $a$ can be produced by starting with either $9$ and $2$ , and then writing down $|9-2|=7$ , or starting with $9$ and $7$ and writing down $|9-7|=2$ . So $2$ , $7$ , and $9$ are all valid answers, because they all appear in at least one valid pair.

For the second test case, we can show that the two initial numbers must have been $-4$ and $11$ .

For the fourth test case, the starting numbers could have been either $3$ and $3$ , or $3$ and $0$ , so $3$ and $0$ are both valid answers.

For the fifth test case, we can show that the starting numbers were $8$ and $16$ .

首页