String Streak

#include <bits/stdc++.h>

using namespace std;
string A;
int k, n;
int power(int x, unsigned int y)
{
    int res = 1;
    while (y > 0)
    {
        if (y & 1)
            res = res * x;

        y = y >> 1;
        x = x * x;
    }
    return res;
}
int findLen(string& A, int n, int k, char ch)
{
    int maxlen = 1;
    int cnt = 0;
    int l = 0, r = 0;
    while(r < n)
    {
        if(A[r] != ch)
            ++cnt;
        while(cnt > k)
        {
            if(A[l] != ch)
                --cnt;
            ++l;
        }
        maxlen = max(maxlen, r - l + 1);
        ++r;
    }
    return maxlen;
}
int answer(string& A, int n, int k)
{
    int maxlen = 1;
    for(int i = 0; i < 26; ++i)
        maxlen = max(maxlen, findLen(A, n, k, i+'a'));
    return maxlen;
}
int main()
{
    getline(cin,A);
    cin>>k;
    n=A.size();
    cout<<answer(A,n,k);
    return 0;
}