P1566 Addition Equation

For an integer set, we define an "addition equation" as follows: some element of the set can be expressed as the sum of other elements in the set. For example, in the set ${1,2,3}$, there is one addition equation: $3=1+2$. Moreover, $3=1+2$ and $3=2+1$ are the same addition equation, and it is the only addition equation of this set. Given an integer set, write a program to find the number of its addition equations.

The first line contains $t$, indicating the number of test cases. The next $t$ lines each describe one test case. Each line starts with an integer $m$, the number of elements in the set, followed by $m$ distinct integers $x_i$, which are the elements of the set.

For each test case, output one integer, the number of addition equations in the set.

$1\le t\le 10$，$1\le m \le 30$，$1\le x\le 1000$。 Translated by ChatGPT 5