Fedya and Array

Description:

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 1000$$$). Description of the test cases follows.

Each line of each test case contain two integers $$$x$$$ and $$$y$$$ ($$$-10^{9} \le y < x \le 10^{9}$$$) — the sum of local maximums and the sum of local minimums, respectively.

Output:

For each test case, in the first line print one integer $$$n$$$ — the minimum length of matching arrays.

In the second line print $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ ($$$-10^{9} \leqslant a_i \leqslant 10^{9}$$$) — the array elements such that the the absolute difference between each pair of neighboring is equal to $$$1$$$.

If there are multiple solutions, print any of them.

It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$2 \cdot 10^{5}$$$.

Sample Input:

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

Sample Output:

10
0 1 2 1 0 -1 0 -1 0 1
16
-2 -1 -2 -1 0 1 2 3 4 5 4 3 2 1 0 -1 
6
1 0 -1 0 1 0
16
2 3 2 1 0 -1 0 -1 0 -1 0 1 2 1 0 1

Note:

In the first test case, the local maximums are the numbers at $$$3, 7$$$ and $$$10$$$ positions, and the local minimums are the numbers at $$$1, 6$$$ and $$$8$$$ positions. $$$x = a_3 + a_7 + a_{10} = 2 + 0 + 1 = 3$$$, $$$y = a_1 + a_6 + a_8 = 0 + (-1) + (-1) = -2$$$.

In the second test case, the local maximums are the numbers at $$$2$$$ and $$$10$$$ positions, and the local minimums are the numbers at $$$1$$$ and $$$3$$$ positions. $$$x = a_2 + a_{10} = -1 + 5 = 4$$$, $$$y = a_1 + a_3 = -2 + (-2) = -4$$$.

In the third test case, the local maximums are the numbers at $$$1$$$ and $$$5$$$ positions, and the local minimums are the numbers at $$$3$$$ and $$$6$$$ positions.