Subset with Zero Sum

Description:

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 10^6$$$). The description of the test cases follows.

The first line of each test case contains a single integer $$$n$$$ ($$$1\le n \le 10^6$$$).

The second line of each test case contains $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$ ($$$i-n \le a_i \le i-1$$$).

It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$10^6$$$.

Output:

For each test case, output two lines.

In the first line, output $$$s$$$ ($$$1\le s \le n$$$) — the number of elements in your subset.

In the second line, output $$$s$$$ integers $$$i_1, i_2, \dots, i_s$$$ ($$$1\le i_k \le n$$$). All integers have to be pairwise different, and $$$a_{i_1} + a_{i_2} + \dots + a_{i_s}$$$ has to be equal to $$$0$$$. If there are several possible subsets with zero-sum, you can find any of them.

Sample Input:

2
5
0 1 2 3 4
4
-3 1 1 1

Sample Output:

1
1 
4
1 4 3 2 

Note:

In the first example, we get sum is $$$a_1 = 0$$$.

In the second example, we get sum is $$$a_1 + a_4 + a_3 + a_2 = 0$$$.