CodeTON Round 3 (Div. 1 + Div. 2, Rated, Prizes!)
D
Count GCD
Codeforces
1800
原题
← CE →
翻译中…

You are given two integers $n$ and $m$ and an array $a$ of $n$ integers. For each $1 \le i \le n$ it holds that $1 \le a_i \le m$.

翻译中…

Your task is to count the number of different arrays $b$ of length $n$ such that:

翻译中…
  • $1 \le b_i \le m$ for each $1 \le i \le n$, and
  • $\gcd(b_1,b_2,b_3,...,b_i) = a_i$ for each $1 \le i \le n$.
翻译中…

Here $\gcd(a_1,a_2,\dots,a_i)$ denotes the greatest common divisor (GCD) of integers $a_1,a_2,\ldots,a_i$.

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Since this number can be too large, print it modulo $998\,244\,353$.

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Input

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Each test consist of multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 100$) — the number of test cases. The description of test cases follows.

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The first line of each test case contains two integers $n$ and $m$ ($1 \le n \le 2 \cdot 10^5$, $1 \le m \le 10^9$) — the length of the array $a$ and the maximum possible value of the element.

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The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \le a_i \le m$) — the elements of the array $a$.

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It is guaranteed that the sum of $n$ across all test cases doesn't exceed $2 \cdot 10^5$.

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Output

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For each test case, print a single integer — the number of different arrays satisfying the conditions above. Since this number can be large, print it modulo $998\,244\,353$.

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Note

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In the first test case, the possible arrays $b$ are:

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  • $[4,2,1]$;
  • $[4,2,3]$;
  • $[4,2,5]$.
翻译中…

In the second test case, the only array satisfying the demands is $[1,1]$.

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In the third test case, it can be proven no such array exists.

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样例

Input #1
5
3 5
4 2 1
2 1
1 1
5 50
2 3 5 2 3
4 1000000000
60 30 1 1
2 1000000000
1000000000 2
Output #1
3
1
0
595458194
200000000
InputCopy OutputCopy
题目信息
题号
1750D
时间限制
2 s
内存限制
256 MB
标签
组合数学
数学
数论

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。