题库练习 Xor of 3
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A14514 | Xor of 3

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题目描述

You are given a sequence $a$ of length $n$ consisting of $0$ s and $1$ s.

You can perform the following operation on this sequence:

- Pick an index $i$ from $1$ to $n-2$ (inclusive).
- Change all of $a_{i}$ , $a_{i+1}$ , $a_{i+2}$ to $a_{i} \oplus a_{i+1} \oplus a_{i+2}$ simultaneously, where $\oplus$ denotes the [bitwise XOR operation](https://en.wikipedia.org/wiki/Bitwise_operation#XOR)

Find a sequence of at most $n$ operations that changes all elements of $a$ to $0$ s or report that it's impossible.We can prove that if there exists a sequence of operations of any length that changes all elements of $a$ to $0$ s, then there is also such a sequence of length not greater than $n$ .

输入格式

Each test contains multiple test cases. The first line contains the number of test cases $t$ ( $1 \le t \le 10^4$ ).

The first line of each test case contains a single integer $n$ ( $3 \le n \le 2\cdot10^5$ ) — the length of $a$ .

The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ( $a_i = 0$ or $a_i = 1$ ) — elements of $a$ .

It is guaranteed that the sum of $n$ over all test cases does not exceed $2\cdot10^5$ .

输出格式

For each test case, do the following:

- if there is no way of making all the elements of $a$ equal to $0$ after performing the above operation some number of times, print "NO".
- otherwise, in the first line print "YES", in the second line print $k$ ( $0 \le k \le n$ ) — the number of operations that you want to perform on $a$ , and in the third line print a sequence $b_1, b_2, \dots, b_k$ ( $1 \le b_i \le n - 2$ ) — the indices on which the operation should be applied.

If there are multiple solutions, you may print any.

输入输出样例

输入 #1
3
3
0 0 0
5
1 1 1 1 0
4
1 0 0 1
输出 #1
YES
0
YES
2
3 1
NO
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