Problem D
Dihedral Group
In mathematics, the dihedral group $D_ n$ is the group of symmetries of a regular $n$-gon. Rotations and reflections are elements of $D_ n$, and in fact all elements of the dihedral group can be expressed as a series of rotations and reflections. Elements of $D_ n$ act on the $n$-gon by permuting its vertices. For example, consider a regular pentagon with vertices initially labeled $1$, $3$, $5$, $4$, $2$ (clockwise, starting from the top):
Applying the above three dihedral actions to the pentagon (a rotation, reflection, and then another rotation) produces the following relabelings of the pentagon’s vertices:
You are given an arbitrary clockwise labeling of the vertices of a regular $n$-gon using the integers $1$ through $n$, and a second sequence to test. Determine whether it’s possible to apply some series of dihedral actions to the $n$-gon so that the test sequence appears as a contiguous clockwise sequence of vertex labels on the transformed polygon.
Input
The first line of input has two integers $n$ and $m$, ($1 \leq m \leq n \leq 5 \cdot 10^{4}$) where $n$ is the number of vertices of the polygon and $m$ is the length of the sequence to be tested.
The next line contains $n$ space-separated integers $d$ ($1 \le d \le n$). This is the initial labeling of the polygon vertices. It is guaranteed that each integer from $1$ to $n$ appears exactly once.
The next line contains $m$ space-separated integers $t$ ($1 \le t \le n$). This is the sequence to be tested.
Output
Output a single integer, which is $1$ if the test sequence could appear as a contiguous sequence of vertex labels after applying some series of dihedral actions to the initial polygon, and $0$ otherwise.
Sample Input 1 | Sample Output 1 |
---|---|
3 3 1 2 3 1 3 2 |
1 |
Sample Input 2 | Sample Output 2 |
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3 1 1 2 3 1 |
1 |
Sample Input 3 | Sample Output 3 |
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4 2 1 2 3 4 1 3 |
0 |
Sample Input 4 | Sample Output 4 |
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4 4 1 2 3 4 2 3 4 1 |
1 |
Sample Input 5 | Sample Output 5 |
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4 4 1 2 3 4 3 2 1 4 |
1 |
Sample Input 6 | Sample Output 6 |
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5 3 1 3 5 4 2 2 1 3 |
1 |
Sample Input 7 | Sample Output 7 |
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5 4 1 3 5 4 2 2 1 5 3 |
0 |