Score : 500 points
Takahashi has a string S of length N consisting of digits from 0
through 9
.
He loves the prime number P. He wants to know how many non-empty (contiguous) substrings of S - there are N \times (N + 1) / 2 of them - are divisible by P when regarded as integers written in base ten.
Here substrings starting with a 0
also count, and substrings originated from different positions in S are distinguished, even if they are equal as strings or integers.
Compute this count to help Takahashi.
Input is given from Standard Input in the following format:
N P S
Print the number of non-empty (contiguous) substrings of S that are divisible by P when regarded as an integer written in base ten.
4 3 3543
6
Here S = 3543
. There are ten non-empty (contiguous) substrings of S:
3
: divisible by 3.
35
: not divisible by 3.
354
: divisible by 3.
3543
: divisible by 3.
5
: not divisible by 3.
54
: divisible by 3.
543
: divisible by 3.
4
: not divisible by 3.
43
: not divisible by 3.
3
: divisible by 3.
Six of these are divisible by 3, so print 6.
4 2 2020
10
Here S = 2020
. There are ten non-empty (contiguous) substrings of S, all of which are divisible by 2, so print 10.
Note that substrings beginning with a 0
also count.
20 11 33883322005544116655
68