Xmas Lights OIS

#include <algorithm>
#include <iostream>
#include <set>
#include <vector>

using namespace std;

int main(void) {
  int N, K;
  cin >> N >> K;
  vector<int> bulbs(N, 0);
  for (int &bulb : bulbs) {
    cin >> bulb;
  }

  vector<int> d_map(K, 0);
  int c_min = numeric_limits<int>::max();

  int i = 0, j = 0, current_bulbs = 0;
  while (i < N && j < N) {
    if (current_bulbs < K) {
      // Increasing window
      if (d_map.at(bulbs.at(i)) == 0) {
        d_map.at(bulbs.at(i))++;
        current_bulbs++;
      } else {
        d_map.at(bulbs.at(i))++;
      }
      i++;
    } else {
      // Decreasing window
      if (d_map.at(bulbs.at(j)) == 1) {
        d_map.at(bulbs.at(j))--;
        current_bulbs--;
      } else {
        d_map.at(bulbs.at(j))--;
      }
      j++;
    }

    if (current_bulbs == K) {
      c_min = min(c_min, i - j);
    }
  }

  cout << c_min;
  return 0;
}