Codeforces Round 868 (Div. 2) |
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Finished |
Consider an array $$$a_1, a_2, \dots, a_n$$$ consisting of numbers $$$1$$$ and $$$-1$$$. Define $$$A$$$-characteristic of this array as a number of pairs of indices $$$1 \le i < j \le n$$$, such that $$$a_i \cdot a_j = 1$$$.
Find any array $$$a$$$ with given length $$$n$$$ with $$$A$$$-characteristic equal to the given value $$$k$$$.
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 100$$$). The description of the test cases follows.
The only line of each test case contains two integers $$$n$$$ and $$$k$$$ ($$$2 \le n \le 100$$$; $$$0 \le k \le \frac{(n-1) n}{2}$$$) — the length of required array and required $$$A$$$-characteristic.
For each test case, if there is no array $$$a$$$ with given $$$A$$$-characteristic $$$k$$$, print NO.
Otherwise, print YES and $$$n$$$ numbers $$$1$$$ and $$$-1$$$, which form the required array $$$a$$$. If there are multiple answers, print any of them.
72 02 13 13 23 35 45 5
YES 1 -1 YES 1 1 YES 1 -1 1 NO YES 1 1 1 YES -1 1 -1 1 1 NO
In the first test case, there is only one pair of different elements in the array, and their product is $$$a_1 \cdot a_2 = -1 \neq 1$$$, hence its $$$A$$$-characteristic is $$$0$$$.
In the second test case, there is only one pair of different elements in the array, and their product is $$$a_1 \cdot a_2 = 1$$$, hence its $$$A$$$-characteristic is $$$1$$$.
In the third test case, there are three pairs of different elements in the array, and their product are: $$$a_1 \cdot a_2 = -1$$$, $$$a_1 \cdot a_3 = 1$$$, $$$a_2 \cdot a_3 = -1$$$, hence its $$$A$$$-characteristic is $$$1$$$.
In the fourth test case, we can show, that there is no array with length $$$3$$$, which $$$A$$$-characteristic is $$$2$$$.
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