Submission #996852

#	Time	Username	Problem	Language	Result	Execution time	Memory
996852		vako_p	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	771 ms	57232 KiB

ho_t2

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back

const int mxN = 3e5 + 5;
ll n,k;
string s;
map<ll,map<char,ll>> p;

ll find(char ch, ll i){
	ll l = i - 1, r = n;
	while(r > l + 1){
		ll mid = l + (r - l) / 2;
		if(i == 0){
			if(p[mid][ch] >= k) r = mid;
			else l = mid;
			continue;
		} 
		if(p[mid][ch] - p[i - 1][ch] >= k) r = mid;
		else l = mid;
	}
	return r;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> k >> s;
	for(int i = 0; i < n; i++){
		if(i != 0){
			p[i]['J'] = p[i - 1]['J'];
			p[i]['O'] = p[i - 1]['O'];
			p[i]['I'] = p[i - 1]['I'];
		}
		p[i][s[i]]++;
	}
	ll ans = 1e9;
	for(int i = 0; i < n; i++){
		if(s[i] == 'J'){
			ll r = find('J', i);
			r = find('O', r);
			r = find('I', r);
			if(r == n) continue;
			ans = min(ans, r - i + 1 - 3 * k);
		}
	}
	if(ans == 1e9) cout << -1;
	else cout << ans;
}	 

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