CF BUDDY
← Problems·

1978C · Manhattan Permutations

1300 · constructive algorithms, data structures, greedy

Problem: Let's call the Manhattan value of a permutation^{\dagger} pp the value of the expression p11+p22++pnn|p_1 - 1| + |p_2 - 2| + \ldots + |p_n - n|.

For example, for the permutation [1,2,3][1, 2, 3], the Manhattan value is 11+22+33=0|1 - 1| + |2 - 2| + |3 - 3| = 0, and for the permutation [3,1,2][3, 1, 2], the Manhattan value is 31+12+23=2+1+1=4|3 - 1| + |1 - 2| + |2 - 3| = 2 + 1 + 1 = 4.

You are given integers nn and kk. Find a permutation pp of length nn such that its Manhattan value is equal to kk, or determine that no such permutation exists.

^{\dagger}A permutation of length nn is an array consisting of nn distinct integers from 11 to nn in arbitrary order. For example, [2,3,1,5,4][2,3,1,5,4] is a permutation, but [1,2,2][1,2,2] is not a permutation (22 appears twice in the array), and [1,3,4][1,3,4] is also not a permutation (n=3n=3 but there is 44 in the array).

Input Format: Each test consists of multiple test cases. The first line contains a single integer tt (1t1041 \leq t \leq 10^{4}) — the number of test cases. The description of the test cases follows.

The only line of each test case contains two integers nn and kk (1n2105,0k10121 \le n \le 2 \cdot 10^{5}, 0 \le k \le 10^{12}) — the length of the permutation and the required Manhattan value.

It is guaranteed that the sum of nn over all test cases does not exceed 21052 \cdot 10^{5}.

Output Format: For each test case, if there is no suitable permutation, output "No". Otherwise, in the first line, output "Yes", and in the second line, output nn distinct integers p1,p2,,pnp_1, p_2, \ldots, p_n (1pin1 \le p_i \le n) — a suitable permutation.

If there are multiple solutions, output any of them.

You can output the answer in any case (for example, the strings "yEs", "yes", "Yes", and "YES" will be recognized as a positive answer).

Note: In the first test case, the permutation [3,1,2][3, 1, 2] is suitable, its Manhattan value is 31+12+23=2+1+1=4|3 - 1| + |1 - 2| + |2 - 3| = 2 + 1 + 1 = 4.

In the second test case, it can be proven that there is no permutation of length 44 with a Manhattan value of 55.

In the third test case, the permutation [1,2,3,4,5,6,7][1,2,3,4,5,6,7] is suitable, its Manhattan value is 11+22+33+44+55+66+77=0|1-1|+|2-2|+|3-3|+|4-4|+|5-5|+|6-6|+|7-7|=0.

Sample Cases

Case 1

Input

8
3 4
4 5
7 0
1 1000000000000
8 14
112 777
5 12
5 2

Output

Yes
3 1 2
No
Yes
1 2 3 4 5 6 7
No
Yes
8 2 3 4 5 6 1 7
No
Yes
5 4 3 1 2
Yes
2 1 3 4 5

Similar problems

00:00:00
Loading editor…
Welcome! I'm your coding tutor for this problem. Use the chips below to reveal stored hints or get AI feedback on your code. I'll guide you step by step — never giving away the solution.

Sign in to unlock AI tutor feedback