Submission #250230

#	Time	Username	Problem	Language	Result	Execution time	Memory
250230		errorgorn	Palindromes (APIO14_palindrome)	C++14	100 / 100	32 ms	35080 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ll,ii>
#define endl '\n'

int edges[300005][26];
int backedge[300005];
int len[300005];

int PREV=0;
int INDEX=1;

int cnt[300005];

string s;
int main(){
	ios::sync_with_stdio(0);
    cin.tie(0);
	
	cin>>s;
	
	memset(edges,-1,sizeof(edges));
	backedge[0]=0,backedge[1]=0;
	len[0]=-1,len[1]=0;
	
	for (int x=0;x<s.size();x++){
		while (s[x-len[PREV]-1]!=s[x]) PREV=backedge[PREV];
		
		if (edges[PREV][s[x]-'a']==-1) edges[PREV][s[x]-'a']=++INDEX;
		int curr=edges[PREV][s[x]-'a'];
		len[curr]=len[PREV]+2;
		
		if (len[curr]==1){
			backedge[curr]=1;
		}
		else{
			int b=backedge[PREV];
			while (s[x-len[b]-1]!=s[x]) b=backedge[b];
			backedge[curr]=edges[b][s[x]-'a'];
		}
		
		PREV=curr;
		
		cnt[curr]++;
		//cout<<curr<<endl;
	}
	
	ll best=0;
	
	for (int x=INDEX;x>1;x--){
		best=max(best,(ll)cnt[x]*len[x]);
		cnt[backedge[x]]+=cnt[x];
	}
	
	cout<<best<<endl;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:28:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int x=0;x<s.size();x++){
               ~^~~~~~~~~

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