#P4349. [CERC2015] Digit Division
[CERC2015] Digit Division
Description
We are given a sequence of n decimal digits. The sequence needs to be partitioned into one or more contiguous subsequences such that each subsequence, when interpreted as a decimal number, is divisible by a given integer m.
Find the number of different such partitions modulo . When determining if two partitions are different, we only consider the locations of subsequence boundaries rather than the digits themselves, e.g. partitions and are considered different.
Input Format
The first line contains two integers n and m (1≤n≤300000, 1≤m≤1000000) – the length of the sequence and the divisor respectively. The second line contains a string consisting of exactly n digits.
Output Format
Output a single integer – the number of different partitions modulo 109 +7.
4 2
1246
4
4 7
2015
0
Hint
Central Europe Regional Contest 2015 Problem D
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