27487번 - One and Two 다국어

You are given a sequence $a_1, a_2, \ldots, a_n$. Each element of $a$ is $1$ or $2$.

Find out if an integer $k$ exists so that the following conditions are met.

• $1 \leq k \leq n-1$, and
• $a_1 \cdot a_2 \cdot \ldots \cdot a_k = a_{k+1} \cdot a_{k+2} \cdot \ldots \cdot a_n$.

If there exist multiple $k$ that satisfy the given condition, print the smallest.

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 100$). Description of the test cases follows.

The first line of each test case contains one integer $n$ ($2 \leq n \leq 1000$).

The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \leq a_i \leq 2$).

For each test case, if there is no such $k$, print $-1$.

Otherwise, print the smallest possible $k$.