Codeforces Round 908 (Div. 1) |
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Finished |
You are given an array $$$b_1, b_2, \ldots, b_n$$$.
An anonymous informant has told you that the array $$$b$$$ was obtained as follows: initially, there existed an array $$$a_1, a_2, \ldots, a_n$$$, after which the following two-component operation was performed $$$k$$$ times:
As a result of $$$k$$$ such operations, the array $$$b_1, b_2, \ldots, b_n$$$ was obtained. You want to check if the words of the anonymous informant can be true or if they are guaranteed to be false.
$$$^{\dagger}$$$A number $$$x$$$ is called a fixed point of the array $$$a_1, a_2, \ldots, a_n$$$ if $$$1 \leq x \leq n$$$ and $$$a_x = x$$$.
$$$^{\ddagger}$$$A cyclic left shift of the array $$$a_1, a_2, \ldots, a_n$$$ is the array $$$a_2, \ldots, a_n, a_1$$$.
Each test contains multiple test cases. The first line contains an integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases. The description of the test cases follows.
The first line of each test case contains two integers $$$n, k$$$ ($$$1 \le n \le 2 \cdot 10^5$$$, $$$1 \le k \le 10^9$$$) — the length of the array $$$b$$$ and the number of operations performed.
The second line of each test case contains $$$n$$$ integers $$$b_1, b_2, \ldots, b_n$$$ ($$$1 \le b_i \le 10^9$$$) — the elements of the array $$$b$$$.
It is guaranteed that the sum of the values of $$$n$$$ for all test cases does not exceed $$$2 \cdot 10^5$$$.
For each test case, output "Yes" if the words of the anonymous informant can be true, and "No" if they are guaranteed to be false.
65 34 3 3 2 33 1007 2 15 56 1 1 1 11 100000000018 489 10 11 12 13 14 15 82 11 42
Yes Yes No Yes Yes No
In the first test case, the array $$$a$$$ could be equal to $$$[3, 2, 3, 4, 3]$$$. In the first operation, a fixed point $$$x = 2$$$ was chosen, and after $$$2$$$ left shifts, the array became $$$[3, 4, 3, 3, 2]$$$. In the second operation, a fixed point $$$x = 3$$$ was chosen, and after $$$3$$$ left shifts, the array became $$$[3, 2, 3, 4, 3]$$$. In the third operation, a fixed point $$$x = 3$$$ was chosen again, and after $$$3$$$ left shifts, the array became $$$[4, 3, 3, 2, 3]$$$, which is equal to the array $$$b$$$.
In the second test case, the array $$$a$$$ could be equal to $$$[7, 2, 1]$$$. After the operation with a fixed point $$$x = 2$$$, the array became $$$[1, 7, 2]$$$. Then, after the operation with a fixed point $$$x = 1$$$, the array returned to its initial state $$$[7, 2, 1]$$$. These same $$$2$$$ operations (with $$$x = 2$$$, and $$$x = 1$$$) were repeated $$$49$$$ times. So, after $$$100$$$ operations, the array returned to $$$[7, 2, 1]$$$.
In the third test case, it can be shown that there is no solution.
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