Codeforces Round 970 (Div. 3) |
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Finished |
A beautiful binary matrix is a matrix that has ones on its edges and zeros inside.
Today, Sakurako was playing with a beautiful binary matrix of size $$$r \times c$$$ and created a binary string $$$s$$$ by writing down all the rows of the matrix, starting from the first and ending with the $$$r$$$-th. More formally, the element from the matrix in the $$$i$$$-th row and $$$j$$$-th column corresponds to the $$$((i-1)*c+j)$$$-th element of the string.
You need to check whether the beautiful matrix from which the string $$$s$$$ was obtained could be squared. In other words, you need to check whether the string $$$s$$$ could have been build from a square beautiful binary matrix (i.e., one where $$$r=c$$$).
The first line contains a single integer $$$t$$$ ($$$1 \le t \le 10^4$$$) — the number of test cases.
The first line of each test case contains a single integer $$$n$$$ ($$$2 \le n \le 2 \cdot 10^5$$$) — the length of the string.
The second line of each test case contains the string $$$s$$$ of length $$$n$$$. The string is always the result of writing out the strings of a beautiful matrix.
It is guaranteed that the sum of $$$n$$$ across all test cases does not exceed $$$2 \cdot 10^5$$$.
Print "Yes", if the original matrix could have been square, and "No" otherwise.
5211411119111101111911111111112111110011111
No Yes Yes No No
For the second test case, string 1111 can be obtained from the matrix:
$$$1$$$ | $$$1$$$ |
$$$1$$$ | $$$1$$$ |
For the third test case, string 111101111 can be obtained from the matrix:
$$$1$$$ | $$$1$$$ | $$$1$$$ |
$$$1$$$ | $$$0$$$ | $$$1$$$ |
$$$1$$$ | $$$1$$$ | $$$1$$$ |
There is no square matrix in the fourth case, such that the string can be obtained from it.
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