Envío 2196

Código

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

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

  map<int, int> map_count;
  int left = 0;
  int longest = 0;
  for (int right = 0; right < word.size(); right++) {
    char letter = word[right];
    map_count[letter]++;
    while (map_count.size() > k) {
      char left_char = word[left];
      map_count[left_char]--;
      if (map_count[left_char] == 0) {
        map_count.erase(left_char);
      }
      left++;
    }
    longest = max(longest, right - left + 1);
  }
  cout << longest << endl;
}