Codeforces Round 536 (Div. 2)
F
Lunar New Year and a Recursive Sequence
Codeforces
2400
原题
← E→
翻译中…

Lunar New Year is approaching, and Bob received a gift from his friend recently — a recursive sequence! He loves this sequence very much and wants to play with it.

翻译中…

Let $f_1, f_2, \ldots, f_i, \ldots$ be an infinite sequence of positive integers. Bob knows that for $i \gt k$, $f_i$ can be obtained by the following recursive equation:

翻译中…

$$f_i = \left(f_{i - 1} ^ {b_1} \cdot f_{i - 2} ^ {b_2} \cdot \cdots \cdot f_{i - k} ^ {b_k}\right) \bmod p,$$

翻译中…

which in short is

翻译中…

$$f_i = \left(\prod_{j = 1}^{k} f_{i - j}^{b_j}\right) \bmod p,$$

翻译中…

where $p = 998\,244\,353$ (a widely-used prime), $b_1, b_2, \ldots, b_k$ are known integer constants, and $x \bmod y$ denotes the remainder of $x$ divided by $y$.

翻译中…

Bob lost the values of $f_1, f_2, \ldots, f_k$, which is extremely troublesome – these are the basis of the sequence! Luckily, Bob remembers the first $k - 1$ elements of the sequence: $f_1 = f_2 = \ldots = f_{k - 1} = 1$ and the $n$-th element: $f_n = m$. Please find any possible value of $f_k$. If no solution exists, just tell Bob that it is impossible to recover his favorite sequence, regardless of Bob's sadness.

翻译中…

Input

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The first line contains a positive integer $k$ ($1 \leq k \leq 100$), denoting the length of the sequence $b_1, b_2, \ldots, b_k$.

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The second line contains $k$ positive integers $b_1, b_2, \ldots, b_k$ ($1 \leq b_i \lt p$).

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The third line contains two positive integers $n$ and $m$ ($k \lt n \leq 10^9$, $1 \leq m \lt p$), which implies $f_n = m$.

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Output

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Output a possible value of $f_k$, where $f_k$ is a positive integer satisfying $1 \leq f_k \lt p$. If there are multiple answers, print any of them. If no such $f_k$ makes $f_n = m$, output $-1$ instead.

翻译中…

It is easy to show that if there are some possible values of $f_k$, there must be at least one satisfying $1 \leq f_k \lt p$.

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Note

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In the first sample, we have $f_4 = f_3^2 \cdot f_2^3 \cdot f_1^5$. Therefore, applying $f_3 = 4$, we have $f_4 = 16$. Note that there can be multiple answers.

翻译中…

In the third sample, applying $f_7 = 1$ makes $f_{23333} = 1$.

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In the fourth sample, no such $f_1$ makes $f_{88888} = 66666$. Therefore, we output $-1$ instead.

翻译中…

样例

Input #1
3
2 3 5
4 16
Output #1
4
InputCopy OutputCopy
Input #2
5
4 7 1 5 6
7 14187219
Output #2
6
InputCopy OutputCopy
Input #3
8
2 3 5 6 1 7 9 10
23333 1
Output #3
1
InputCopy OutputCopy
Input #4
1
2
88888 66666
Output #4
-1
InputCopy OutputCopy
Input #5
3
998244352 998244352 998244352
4 2
Output #5
-1
InputCopy OutputCopy
Input #6
10
283 463 213 777 346 201 463 283 102 999
2333333 6263423
Output #6
382480067
InputCopy OutputCopy
题目信息
题号
1106F
时间限制
3 s
内存限制
256 MB
标签
数学
矩阵
数论

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