A-FlippedCards

/// sol OF
#include<bits/stdc++.h>
using namespace std;
ifstream fin("flipc.in");
ofstream fout("flipc.out");
void solve1() {
    long long n, K;
    fin >> n >> K;
    long long v[n + 5], k(0);
    bool vl[n + 5];
    char a('X');
    for (long long i = 1; i <= n; i++) {
        char c;
        fin >> c;
        if (c != a)v[++k] = 1, vl[k] = (c == '1');
        else v[k]++;
        a = c;
    }
    long long s[k + 5];
    s[0] = 0;
    for (long long i = 1; i <= k; i++)s[i] = s[i - 1] + v[i];
    long long mx(0);
    for (long long i = 1; i + K - 1 <= k; i++) {
        if (vl[i] && i + K <= k)mx = max(mx, s[i + K] - s[i - 1]);
        else mx = max(mx, s[i + K - 1] - s[i - 1]);
    }
    fout << mx;
}
void solve2() {
    long long n, K;
    fin >> n >> K;
    long long v[n + 5], k(0);
    bool vl[n + 5];
    char a('X');
    for (long long i = 1; i <= n; i++) {
        char c;
        fin >> c;
        if (c != a)v[++k] = 1, vl[k] = (c == '1');
        else v[k]++;
        a = c;
    }
    long long nr(0);
    for (long long i = 1; i + K - 1 <= k; i++) {
        if (vl[i]) {
            if (i + K <= k) {
                nr += v[i] * v[i + K];
            }
        }
        else {
            if (K == 1)nr += (v[i] * (v[i] + 1)) / 2;
            else nr += v[i] * v[i + K - 1];
        }
    }
    fout << nr;
}
int main() {
    long long c;
    fin >> c;
    if (c == 1)solve1();
    else solve2();
    return 0;
}