Submission #1129587

#	Time	Username	Problem	Language	Result	Execution time	Memory
1129587		am_aadvik	JJOOII 2 (JOI20_ho_t2)	C++20	13 / 100	2095 ms	11480 KiB

ho_t2

#include <iostream>
#include <vector>
using namespace std;

int nxtk(string& s, int i, vector<vector<int>>& pre, int j, int k) {
	int ans = j;
	for (int x = 0; ((x < k) && (ans != -1)); ++x)
		ans = pre[ans][i] + 1;
	return ans;
}

int main()
{
	int n, k; cin >> n >> k;
	string s, l = "JOI"; cin >> s;
	vector<vector<int>> pre(n + 1, vector<int>(3, -2));
	for (int i = 0; i < 3; ++i)
		for (int j = n - 1; j >= 0; --j)
			pre[j][i] = ((s[j] == l[i]) ? j : pre[j + 1][i]);

	int ans = n + 1;
	for (int f = 0; f < n; ++f) {
		int l = f + 2, r = n - 1;
		while (l <= r) {
			int e = (l + r) / 2, j = f;
			bool ok = 1;
			for (int i = 0; i < 3; j--, ++i) {
				j = nxtk(s, i, pre, j, k);
				if ((j == -1) || (j > (e + 1))) { ok = 0; break; }
			}

			if (ok) ans = min(ans, e - f + 1), r = e - 1;
			else l = e + 1;
		}
	}
	cout << ((ans == (n + 1)) ? -1 : ans - (3 * k)) << endl;
}

• Subtask 1: 1 / 1
• Subtask 2: 12 / 12
• Subtask 3: 0 / 87