#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(long long i=0;i<(long long)(n);i++)
#define REP(i,k,n) for(long long i=k;i<(long long)(n);i++)
#define all(a) a.begin(),a.end()
#define pb emplace_back
#define eb emplace_back
#define lb(v,k) (lower_bound(all(v),k)-v.begin())
#define ub(v,k) (upper_bound(all(v),k)-v.begin())
#define fi first
#define se second
#define pi M_PI
#define PQ(T) priority_queue<T>
#define SPQ(T) priority_queue<T,vector<T>,greater<T>>
#define dame(a) {out(a);return 0;}
#define decimal cout<<fixed<<setprecision(15);
#define dupli(a) {sort(all(a));a.erase(unique(all(a)),a.end());}
typedef long long ll;
typedef pair<ll,ll> P;
typedef tuple<ll,ll,ll> PP;
typedef tuple<ll,ll,ll,ll> PPP;
typedef multiset<ll> S;
using vi=vector<ll>;
using vvi=vector<vi>;
using vvvi=vector<vvi>;
using vvvvi=vector<vvvi>;
using vp=vector<P>;
using vvp=vector<vp>;
using vb=vector<bool>;
using vvb=vector<vb>;
const ll inf=1001001001001001001;
const ll INF=1001001001;
const ll mod=1000000007;
const double eps=1e-10;
template<class T> bool chmin(T&a,T b){if(a>b){a=b;return true;}return false;}
template<class T> bool chmax(T&a,T b){if(a<b){a=b;return true;}return false;}
template<class T> void out(T a){cout<<a<<'\n';}
template<class T> void outp(T a){cout<<'('<<a.fi<<','<<a.se<<')'<<'\n';}
template<class T> void outvp(T v){rep(i,v.size())cout<<'('<<v[i].fi<<','<<v[i].se<<')';cout<<'\n';}
template<class T> void outvvp(T v){rep(i,v.size())outvp(v[i]);}
template<class T> void outv(T v){rep(i,v.size()){if(i)cout<<' ';cout<<v[i];}cout<<'\n';}
template<class T> void outvv(T v){rep(i,v.size())outv(v[i]);}
template<class T> bool isin(T x,T l,T r){return (l)<=(x)&&(x)<=(r);}
template<class T> void yesno(T b){if(b)out("yes");else out("no");}
template<class T> void YesNo(T b){if(b)out("Yes");else out("No");}
template<class T> void YESNO(T b){if(b)out("YES");else out("NO");}
template<class T> void noyes(T b){if(b)out("no");else out("yes");}
template<class T> void NoYes(T b){if(b)out("No");else out("Yes");}
template<class T> void NOYES(T b){if(b)out("NO");else out("YES");}
void outs(ll a,ll b){if(a>=inf-100)out(b);else out(a);}
ll gcd(ll a,ll b){if(b==0)return a;return gcd(b,a%b);}
ll modpow(ll a,ll b){ll res=1;a%=mod;while(b){if(b&1)res=res*a%mod;a=a*a%mod;b>>=1;}return res;}
vi manacher(string &s){
int i=0,j=0;
vi res(s.size());
while(i<s.size()){
while(i-j>=0&&i+j<s.size()&&s[i-j]==s[i+j])j++;
res[i]=j;
int k=1;
while(i-k>=0&&k+res[i-k]<j){
res[i+k]=res[i-k];
k++;
}
i+=k;j-=k;
}
return res;
}
ll N,k;
vi rankk,tmp;
bool co(int i,int j){
if(rankk[i]!=rankk[j])return rankk[i]<rankk[j];
int ri= i+k<=N ? rankk[i+k] : -1;
int rj= j+k<=N ? rankk[j+k] : -1;
return ri<rj;
}
vi make(string s){
N=s.size();
vi sa(N+1);
rankk=vi(N+1);tmp=vi(N+1);
rep(i,N+1){
sa[i]=i;rankk[i]= i<N ? s[i] : -1;
}
for(k=1;k<=N;k*=2){
sort(all(sa),co);
tmp[sa[0]]=0;
REP(i,1,N+1)tmp[sa[i]]=tmp[sa[i-1]]+(co(sa[i-1],sa[i])?1:0);
rep(i,N+1)rankk[i]=tmp[i];
}
return sa;
}
int main(){
string s;cin>>s;
string t;
rep(i,s.size()){
if(i)t+='x';
t+=s[i];
}
vi m=manacher(t);
vp q;
rep(i,m.size()){
if(i&1)q.pb(i/2-m[i]/2+1,i/2+m[i]/2);
else q.pb(i/2-(m[i]-1)/2,i/2+(m[i]-1)/2);
}
ll n=s.size();
vi has(n+1);
rep(i,n)has[i+1]=(has[i]*30+(s[i]-'a'))%mod;
vi sa(N+1);
sa=make(s);
vi rs(n+1);
rep(i,n+1)rs[sa[i]]=i;
ll ans=0;
for(auto x:q){
ll ok=rs[x.fi],ng=n+1;
ll len=x.se-x.fi+1;
while(ng-ok>1){
ll md=(ok+ng)/2;
ll id=sa[md];
if(id+len>n){ng=md;continue;}
ll a=(has[x.se+1]-has[x.fi]+mod)%mod;
ll b=(has[id+len]-has[id]+mod)%mod;
if(x.fi<id)a=a*modpow(30,id-x.fi);
else b=b*modpow(30,x.fi-id);
if(a%mod==b%mod)ok=md;
else ng=md;
}
chmax(ans,(ok-rs[x.fi]+1)*len);
}
out(ans);
}
Compilation message
palindrome.cpp: In function 'vi manacher(std::string&)':
palindrome.cpp:57:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
57 | while(i<s.size()){
| ~^~~~~~~~~
palindrome.cpp:58:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
58 | while(i-j>=0&&i+j<s.size()&&s[i-j]==s[i+j])j++;
| ~~~^~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
256 KB |
Output is correct |
| 2 |
Correct |
1 ms |
256 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
256 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
384 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
23 ms |
1272 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
340 ms |
9440 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1075 ms |
27644 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
