Deja vu

2000ms

262144K

Description:

This is an unusual problem in an unusual contest, here is the announcement: http://codeforces.com/blog/entry/73543

You run a string shop. During a day your customers want to buy strings of certain lengths and sometimes satisfying other properties.

Today your first customer asked you if you have a string of length $$$k$$$. In fact, you have a string of length $$$n$$$ and can cut a string of length $$$k$$$ starting at any position out of it. You wonder how many distinct values this string can equal.

Please note that in your shop strings are over an alphabet of size $$$2$$$.

Input:

The first line contains two integers $$$n$$$ and $$$k$$$ ($$$1\leq k\leq n\leq 200\,000$$$). The second line contains a binary string $$$s$$$ of length $$$n$$$.

Output:

In the only line print the number of distinct substrings of length $$$k$$$ of the string $$$s$$$.

Sample Input:

5 2
01101

Sample Output:

Sample Input:

10 3
1110001011

Sample Output:

Note:

The second sample test represents the de Bruijn sequence of order 3.

Informação

Provedor Codeforces

Código CF1302I