Submission #740022

#	Time	Username	Problem	Language	Result	Execution time	Memory
740022		Abrar_Al_Samit	Palindromes (APIO14_palindrome)	C++17	100 / 100	25 ms	35056 KiB

palindrome

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

const int nax = 3e5 + 3;

string s;
int n;

int len[nax], link[nax];
int tree[nax][26];
int occ[nax], t = 1;
int idx = 0;
long long ans = 0;

void extend(int p) {
	while(s[p - len[t] - 1] != s[p]) t = link[t];
	int x = link[t];
	while(s[p - len[x] - 1] != s[p]) x = link[x];
	int c = s[p] - 'a';
	if(!tree[t][c]) {
		tree[t][c] = ++idx;
		len[idx] = len[t] + 2;
		link[idx] = len[idx] == 1 ? 2 : tree[x][c];

	} t = tree[t][c];
	++occ[t];
}
void PlayGround() {
	cin>>s;
	n = s.size();
	s = '#' + s; //1 based indexing (must for this implementation)

	len[1] = -1, link[1] = 1; //odd len root
	len[2] = 0, link[2] = 1; //even len root
	t = idx = 2;

	for(int i=1; i<=n; ++i) {
		extend(i);
	}	

	for(int i=idx; i>2; --i) {
		ans = max(ans, len[i] * 1LL * occ[i]);
		occ[link[i]] += occ[i];
	}

	cout<<ans<<'\n';

	// cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
}
int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	PlayGround();
	return 0;
}

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