Envío 2185

Código

#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    cin >> s;
    int k;
    cin >> k;

    if (k == 26) {
        cout << s.size() << endl;
    } else {
        int start = 0;
        unordered_map<int, int> m;
        int maxSize = 0;
        for (int i = 0; i < s.size(); i++) {
            char c = s[i];
            m[c]++;
            if(m.size() > k) {
                while (m.size() > k) {
                    char st = s[start++];
                    m[st]--;
                    if (m[st] == 0) {
                        m.erase(st);
                    }
                }
            } else {
                maxSize = max(maxSize, i - start + 1);
            }
        }
        cout << maxSize << endl;
    }
}