제출 #243578

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
243578		islingr	회문 (APIO14_palindrome)	C++14	73 / 100	71 ms	73580 KiB

palindrome

// Eertree practice
// Pointer implementation

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

#define rep(i, a, b) for (auto i = (a); i < (b); ++i)
#define trav(e, x) for (auto &e : x)
#define eb(x...) emplace_back(x)
#define all(x) begin(x), end(x)
#define sz(x) int((x).size())

template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

const int A = 26;

using pnode = struct node*;
struct node {
	int len, occ; pnode link, nxt[A];
	node() { fill(nxt, nxt + A, nullptr); }
};

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	string s; cin >> s;
	
	vector<pnode> nodes;
	pnode zero, imag, last;
	
	imag = new node();
	imag->len = -1;
	imag->link = imag;

	zero = new node();
	zero->len = 0;
	zero->link = imag;

	last = zero;

	nodes = {imag, zero};
	rep(i, 0, sz(s)) {
		pnode cur = last;
		while (s[i - cur->len - 1] != s[i]) cur = cur->link;
		auto &tmp = cur->nxt[s[i] - 'a'];
		if (!tmp) {
			tmp = new node();
			tmp->len = cur->len + 2;
			if (cur != imag) {
				cur = cur->link;
				while (s[i - cur->len - 1] != s[i]) cur = cur->link;
				tmp->link = cur->nxt[s[i] - 'a'];
			} else tmp->link = zero;
			nodes.eb(tmp);
		}
		last = tmp;
		++last->occ;
	}

	reverse(all(nodes));
	trav(v, nodes) v->link->occ += v->occ;

	ll ans = 0;
	trav(v, nodes) ckmax(ans, 1ll * v->len * v->occ);
	cout << ans;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 0 / 27