Codeforces Round 330 (Div. 2)
B
Pasha and Phone
Codeforces
1600
原题
← AC →
翻译中…

Pasha has recently bought a new phone jPager and started adding his friends' phone numbers there. Each phone number consists of exactly $*n*$ digits.

翻译中…

Also Pasha has a number $*k*$ and two sequences of length $*n* / *k*$ ($*n*$ is divisible by $*k*$) $*a*_{1}, *a*_{2}, ..., *a*_{*n* / *k*}$ and $*b*_{1}, *b*_{2}, ..., *b*_{*n* / *k*}$. Let's split the phone number into blocks of length $*k*$. The first block will be formed by digits from the phone number that are on positions $1$, $2$,..., $*k*$, the second block will be formed by digits from the phone number that are on positions $*k* + 1$, $*k* + 2$, ..., $2·*k*$ and so on. Pasha considers a phone number good, if the $*i*$-th block doesn't start from the digit $*b*_{*i*}$ and is divisible by $*a*_{*i*}$ if represented as an integer.

翻译中…

To represent the block of length $*k*$ as an integer, let's write it out as a sequence $*c*_{1}$, $*c*_{2}$,...,$*c*_{*k*}$. Then the integer is calculated as the result of the expression $*c*_{1}·10^{*k* - 1} + *c*_{2}·10^{*k* - 2} + ... + *c*_{*k*}$.

翻译中…

Pasha asks you to calculate the number of good phone numbers of length $*n*$, for the given $*k*$, $*a*_{*i*}$ and $*b*_{*i*}$. As this number can be too big, print it modulo $10^{9} + 7$.

翻译中…

Input

翻译中…

The first line of the input contains two integers $*n*$ and $*k*$ ($1 ≤ *n* ≤ 100 000$, $1 ≤ *k* ≤ *min*(*n*, 9)$) — the length of all phone numbers and the length of each block, respectively. It is guaranteed that $*n*$ is divisible by $*k*$.

翻译中…

The second line of the input contains $*n* / *k*$ space-separated positive integers — sequence $*a*_{1}, *a*_{2}, ..., *a*_{*n* / *k*}$ ($1 ≤ *a*_{*i*} < 10^{*k*}$).

翻译中…

The third line of the input contains $*n* / *k*$ space-separated positive integers — sequence $*b*_{1}, *b*_{2}, ..., *b*_{*n* / *k*}$ ($0 ≤ *b*_{*i*} ≤ 9$).

翻译中…

Output

翻译中…

Print a single integer — the number of good phone numbers of length $*n*$ modulo $10^{9} + 7$.

翻译中…

Note

翻译中…

In the first test sample good phone numbers are: 000000, 000098, 005600, 005698, 380000, 380098, 385600, 385698.

翻译中…

样例

Input #1
6 2
38 56 49
7 3 4
Output #1
8
InputCopy OutputCopy
Input #2
8 2
1 22 3 44
5 4 3 2
Output #2
32400
InputCopy OutputCopy
题目信息
题号
595B
时间限制
1 s
内存限制
256 MB
标签
二分
数学

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。