Submission #262094

#	Time	Username	Problem	Language	Result	Execution time	Memory
262094		mohamedsobhi777	Palindromes (APIO14_palindrome)	C++14	100 / 100	96 ms	41076 KiB

palindrome

//#include "elephants.h"
#include<bits/stdc++.h>

#define I inline void 

using namespace std ; 

using ld = long double ; 
using ll = long long ; 

const int N = 3e5  + 7 , mod = 1e9 + 7 ; 

int n;
ll ans ; 
string s;
int num , suf ; 

struct node{
	int nxt[26] ; 
	int len ; 
	int num ; 
	int occ ; 
	int lazy ; 
	int suflnk ; 
} tree[N] ; 


bool addL(int pos){
	int cur = suf , curlen = 0 ; 
	int let = s[pos] - 'a' ; 

	while(1){
		curlen = tree[cur].len ;
		if(pos - 1 - curlen >=0 && s[pos - 1 - curlen ] == s[pos])
			break ; 
		cur = tree[cur].suflnk ;
	}

	if(tree[cur].nxt[let]){
		suf = tree[cur].nxt[let] ; 
		tree[suf].lazy++ ; 
		return 0 ; 
	}

	num ++ ;
	suf = num ;
	tree[num].len = tree[cur].len + 2 ; 
	
	tree[cur].nxt[let] = num ;

	tree[num].lazy ++ ;  

	if(tree[num].len == 1){
		tree[num].suflnk = 2 ; 
		tree[num].lazy = 1; 
		return 1 ; 
	}

	while(1){
		cur = tree[cur].suflnk ; 
		curlen = tree[cur].len ; 
		if(pos -1 - curlen >= 0 && s[pos] == s[pos - 1 - curlen ]){
			tree[num].suflnk = tree[cur].nxt[let] ; 
			break ;
		}
	}

	tree[num].num = 1 + tree[tree[num].suflnk].num ; 

	return 1 ; 
}

I init(){
	suf = num = 2 ; 
	tree[1].len = -1 ; 
	tree[2].len = 0 ; 
	tree[1].suflnk = 1 ; 
	tree[2].suflnk = 1 ; 
}

int pal[N] ; 
int vis[N] ; 

int main(){

	ios_base::sync_with_stdio(0) ; 
	cin.tie(0) ; 
	//freopen("in.in" , "r" , stdin) ; 
	init() ; 
	cin >> s ; 
	n = (int) s.size() ; 
	for(int i = 0 ;i < n ;i++){
		addL(i) ; 
	}	

	priority_queue<int> q ; 

	for(int i = 3 ;i <=num ;i++){
		q.push(i) ; 
	}
	while(q.size()){
		int ret = q.top() ; q.pop() ; 
		if(vis[ret]++)continue ; 
		pal[ret] = tree[ret].lazy ;
		if(tree[ret].suflnk > 2){
			tree[tree[ret].suflnk].lazy+=tree[ret].lazy ; 
			q.push(tree[ret].suflnk) ; 
		}
	}

	for(int i = 3 ;i <= num ;i++){
		ans = max(ans , 1ll * tree[i].len * pal[i] ) ; 
	}

	cout<< ans << endl; 
	return 0 ; 
}

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