Submission #1276950

#	Time	Username	Problem	Language	Result	Execution time	Memory
1276950		Thunnus	Necklace (Subtask 4) (BOI19_necklace4)	C++20	15 / 15	222 ms	584 KiB

necklace

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

int p1[6002], p2[6002];

void fill_p(string s, int *p) {
	for (int i = 1; i < s.size(); i++) {
		int j = p[i - 1];
		while (j && s[i] != s[j]) j = p[j - 1];
		if (s[i] == s[j]) j++;
		p[i] = j;
	}
}

tuple<int, int, int> solve(string s, string t, bool rev) {
	int n = s.size(), m = t.size();
	tuple<int, int, int> ans = {0, 0, 0};
	for (int i = 0; i < n; i++) {
		string s1 = s.substr(0, i), s2 = s.substr(i, n - i);
		reverse(s1.begin(), s1.end());
		string t1 = t, t2 = t;
		reverse(t2.begin(), t2.end());
		fill_p(s1 + "#" + t1, p1), fill_p(s2 + "#" + t2, p2);
		for (int j = 1; j <= m; j++)
			ans = max(ans, {p1[i + j] + p2[n + m - i - j], i - p1[i + j],
			                rev ? m - j - p2[n + m - i - j] : j - p1[i + j]});
	}
	return ans;
}

int main() {
	cin.tie(0)->sync_with_stdio(0);
	string s, t;
	cin >> s >> t;
	tuple<int, int, int> ans = solve(s, t, false);
	reverse(t.begin(), t.end());
	ans = max(ans, solve(s, t, true));
	cout << get<0>(ans) << '\n' << get<1>(ans) << ' ' << get<2>(ans);
	return 0;
}

• Subtask 1: 15 / 15