Submission #757555

#	Time	Username	Problem	Language	Result	Execution time	Memory
757555		vjudge1	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	16 ms	5588 KiB

ho_t2

//
//  main.cpp
//  HAZ
//
//  Created by Nurbek Nurbagi
// 
  
// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
 
#define pb push_back
#define ppb pop_back
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
 
typedef long double ld;
typedef long long ll;
  
using namespace std;
  
int gcd (int a, int b) {
	while (b) {
		a %= b;
		swap (a, b);
	}
	return a;
}
  
const ll N = 2e5 + 7;
const ll mod = 1e9 + 7;
const ll inf = 1e18;
const ld pi = 3.141592653589793;
const ld eps = 1e-12;
const ll zero = 0;
const int A = 1e9 + 5;
  
const int dx[4] = {0, -1, 0, 0};
const int dy[4] = {1, 0, -1, 1};

vector <ll> j(N), o(N), i(N);

void solve() {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    if (n == 3) {
        if (k == 1 and s == "JOI") cout << 0;
        else cout << -1;
        return;
    }
    j[0] = (s[1] == 'J');
    o[0] = (s[1] == 'O');
    i[0] = (s[1] == 'I');
    for (int q = 1; q < n; q++) {
        j[q] = j[q - 1] + (s[q] == 'J');
        o[q] = o[q - 1] + (s[q] == 'O');
        i[q] = i[q - 1] + (s[q] == 'I');
    }
    ll mx = 1e18;
    for(int q = 0; q < n; q++){
        if (s[q] != 'J') continue;
        int l = q;
        int r = n;
        int x = j[q] + k - 1;
        int cnt = 0;
        while (l <= r) {
            int mid = (l + r) / 2;
            if (j[mid] >= x) {
                r = mid - 1;
                cnt = mid;
            }
            else l = mid + 1;
        }
        if (cnt == 0) continue;
        l = cnt + 1;
        r = n;
        x = o[l - 1] + k;
        cnt = 0;
        while(l <= r){
            int mid = (l + r) / 2;
            if (o[mid] >= x) {
                r = mid - 1;
                cnt = mid;
            } 
            else l = mid + 1;
        }
        if (cnt == 0) continue;
        l = cnt + 1;
        r = n;
        x = i[l - 1] + k;
        cnt = 0;
        while(l <= r){
            int mid = (l + r) / 2;
            if (i[mid] >= x) {
                r = mid - 1;
                cnt = mid;
            }
            else l = mid + 1;
        }
        if (cnt == 0) continue;
        mx = min(mx, (ll)cnt - q + 1 - 3 * k);
    }
    if (mx == 1e18) {
        cout << -1;
        return;
    }
    cout << mx;
}

 
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    // freopen("herding.in","r",stdin);
    // freopen("herding.out","w",stdout);
    int t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) solve();
}

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