A14303 | $Array Reodering$

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内存限制256MB

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题目描述

You are given an array $a$ consisting of $n$ integers. Let's call a pair of indices $i$ , $j$ good if $1 \le i < j \le n$ and $\gcd(a_i, 2a_j) > 1$ (where $\gcd(x, y)$ is the greatest common divisor of $x$ and $y$ ). Find the maximum number of good index pairs if you can reorder the array $a$ in an arbitrary way.

The first line contains a single integer $t$ ( $1 \le t \le 1000$ ) — the number of test cases. The first line of the test case contains a single integer $n$ ( $2 \le n \le 2000$ ) — the number of elements in the array. The second line of the test case contains $n$ integers $a_1, a_2, \dots, a_n$ ( $1 \le a_i \le 10^5$ ). It is guaranteed that the sum of $n$ over all test cases does not exceed $2000$ .

For each test case, output a single integer — the maximum number of good index pairs if you can reorder the array $a$ in an arbitrary way.

输入 #1

输出 #1

4
0
9

C++ 编辑器

输入

输出