Submission #922911

#	Time	Username	Problem	Language	Result	Execution time	Memory
922911		viwlesxq	JJOOII 2 (JOI20_ho_t2)	C++17	100 / 100	8 ms	2460 KiB

ho_t2

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define size(x) (int)x.size()
#define all(x) x.begin(), x.end()

template<class S, class T>
bool chmin(S &a, const T &b) {
	return a > b ? (a = b) == b : false;
}
template<class S, class T>
bool chmax(S &a, const T &b) {
	return a < b ? (a = b) == b : false;
}
const int inf = 1e9 + 7;

signed main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	int n, k; cin >> n >> k;
	string s; cin >> s;
	s = '$' + s;
	int res = inf;
	deque<int> J, O, I;
	for (int i = 1; i <= n; ++i) {
		if (s[i] == 'O') O.push_back(i);
		else if (s[i] == 'I' && size(O) >= k) {
			I.push_back(i);
		}
	}
	for (int i = 1; i <= n; ++i) {
		if (s[i] == 'O' && size(J) >= k && size(O) >= k && size(I) >= k) {
			int cur = O[k - 1] - O[0] + 1 - k;
			cur += O[0] - J.back() - 1;
			cur += J.back() - J[size(J) - k] + 1 - k;
			cur += I[0] - O[k - 1] - 1;
			cur += I[k - 1] - I[0] + 1 - k;
			chmin(res, cur);
		}
		if (s[i] == 'J') J.push_back(i);
		else if (s[i] == 'O') {
			O.pop_front();
			if (size(O) < k) break;
			while (!I.empty() && I.front() < O[k - 1]) I.pop_front();
		}
	}
	cout << (res == inf ? -1 : res);
}

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