[EC Final 2021] Future Coder

### 题目描述 共 $T$ 组数据，每组给出一个数 $n$ 和 $n$ 个数 $a_1,a_2,...,a_n$，求有多少个二元组 $(a_i,a_j)$ 满足 $a_ia_j<a_i+a_j$。 ### 输入格式 第一行为一个数 $T$。 接下来 $T$ 组数据，每组数据第一行为一个数 $n$，第二行为 $n$ 个数 $a_1,a_2,...,a_n$。 ### 输出格式 $T$ 行，为满足 $a_ia_j<a_i+a_j$ 的二元组 $(a_i,a_j)$ 的组数。 Translated from [FurippuWRY](https://www.luogu.com.cn/user/993779)。

Prof. Pang builds his famous coding team recently. To pursue a gold medal in ICPC, hundreds of pupils join his team. Unfortunately, one of Prof. Pang's students believes that for any integers $a$ and $b$, $a\times b\ge a+b$. To disprove this proposition, Prof. Pang writes $n$ numbers $a_1,a_2,\ldots, a_n$ on a paper and wants you to count how many pairs of numbers $(a_i, a_j)$ ($1\le i < j\le n$) satisfies $a_i\times a_j<a_i+a_j$.

The first line contains a single integer $T$ ($1\le T\le 10^6$) denoting the number of test cases. For each test case, the first line contains a single integer $n$ ($1\le n\le 10^6$). The second line contains $n$ integers $a_1, a_2, \ldots, a_n$ ($-10^9\le a_i\le 10^9$). It is guaranteed that the sum of $n$ over all test cases will not exceed $10^6$.

For each test case, print one line containing the answer.

2
8
3 -1 4 1 -5 9 2 -6
1
0

19
0