CF1535B.Array Reodering
普及/提高-
通过率:0%
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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≤i<j≤n and gcd(ai,2aj)>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.
输入格式
The first line contains a single integer t ( 1≤t≤1000 ) — the number of test cases.
The first line of the test case contains a single integer n ( 2≤n≤2000 ) — the number of elements in the array.
The second line of the test case contains n integers a1,a2,…,an ( 1≤ai≤105 ).
It is guaranteed that the sum of n over all test cases does not exceed 2000 .
输出格式
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.
输入输出样例
输入#1
3 4 3 6 5 3 2 1 7 5 1 4 2 4 1
输出#1
4 0 9
说明/提示
In the first example, the array elements can be rearranged as follows: [6,3,5,3] .
In the third example, the array elements can be rearranged as follows: [4,4,2,1,1] .