Submission #787772

#	Time	Username	Problem	Language	Result	Execution time	Memory
787772		tvladm2009	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	29 ms	5524 KiB

ho_t2

#include <bits/stdc++.h>

using namespace std;

const int N = (int) 2e5 + 7;
const int INF = (int) 1e9;
int J[N], O[N], I[N];
int whereJ[N], whereO[N], whereI[N];
int n, k;
string s;

signed main() {
  ios::sync_with_stdio(0); cin.tie(0);

  // freopen("input", "r", stdin);

  cin >> n >> k >> s;
  s = "#" + s;
  for (int i = 1; i <= n; i++) {
    J[i] = J[i - 1];
    O[i] = O[i - 1];
    I[i] = I[i - 1];
    if (s[i] == 'J') {
      J[i]++;
    } else if (s[i] == 'O') {
      O[i]++;
    } else {
      I[i]++;
    }
  }
  for (int i = 1; i <= n; i++) {
    int low = 1, high = n;
    while (low <= high) {
      int mid = (low + high) / 2;
      if (J[mid] - J[i - 1] >= k) {
        whereJ[i] = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    int low = 1, high = n;
    while (low <= high) {
      int mid = (low + high) / 2;
      if (O[mid] - O[i - 1] >= k) {
        whereO[i] = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
  }
  for (int i = 1; i <= n; i++) {
    int low = 1, high = n;
    while (low <= high) {
      int mid = (low + high) / 2;
      if (I[mid] - I[i - 1] >= k) {
        whereI[i] = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
  }
  int ret = INF;
  for (int i = 1; i <= n; i++) {
    int j = whereJ[i];
    j = whereO[j];
    j = whereI[j];
    if (j != 0) {
      ret = min(ret, j - i + 1 - 3 * k);
    }
  }
  if (ret == INF) {
    ret = -1;
  }
  cout << ret << "\n";
  return 0;
}

• Subtask 1: 1 / 1
• Subtask 2: 12 / 12
• Subtask 3: 87 / 87