Submission #202359

#	Time	Username	Problem	Language	Result	Execution time	Memory
202359		dolphingarlic	JJOOII 2 (JOI20_ho_t2)	C++14	100 / 100	17 ms	3080 KiB

ho_t2

#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
using namespace std;

int pref[4][200001], ptr[4];

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n, k;
	string s;
	cin >> n >> k >> s;
	FOR(i, 0, n) {
		FOR(j, 1, 4) pref[j][i + 1] = pref[j][i];
		if (s[i] == 'J') pref[1][i + 1]++;
		if (s[i] == 'O') pref[2][i + 1]++;
		if (s[i] == 'I') pref[3][i + 1]++;
	}

	int ans = INT_MAX;
	for (ptr[0] = 0; ptr[0] <= n; ptr[0]++) {
		FOR(i, 1, 4) while (ptr[i] < ptr[i - 1] || (ptr[i] <= n && pref[i][ptr[i]] - pref[i][ptr[i - 1]] < k)) ptr[i]++;
		bool possible = true;
		FOR(i, 1, 4) if (ptr[i] > n || pref[i][ptr[i]] - pref[i][ptr[i - 1]] < k) possible = false;
		if (possible) ans = min(ans, ptr[3] - ptr[0] - 3 * k);
	}
	if (ans == INT_MAX) cout << -1;
	else cout << ans;
	return 0;
}

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