#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define fs first
#define sc second
#define debug(y) cout<<y,exit(0)
using namespace std;
typedef pair<ll,ll> LL;
const ll N = 1e5 + 9;
const ll base = 31;
const ll mod = 1e9 + 7;
ll n,Hash[N][2],pw[N],have[2][N],creat[N][26],ans;
string s[2];
void performHash(){
for (ll i = 1;i <= n;i++)
for (ll j = 0;j < 2;j++){
Hash[i][j] = Hash[i - 1][j]*base + s[j][i] - 'a' + 1;
Hash[i][j] %= mod;
}
}
ll GetHash(ll l,ll r,ll c){
//debug(pw[1]);
//debug(pw[r - l + 1]);
return (Hash[r][c] - Hash[l - 1][c]*pw[r - l + 1] + mod*mod)%mod;
}
bool IsPalin(ll l,ll r){
//debug(GetHash(l,r,0));
//debug(Hash[3][1]);
//debug(GetHash(n - r + 1,n - l + 1,1));
return GetHash(l,r,0) == GetHash(n - r + 1,n - l + 1,1);
}
int main(){
ios_base::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
#define task "tst"
if (fopen(task".inp","r")){
freopen(task".inp","r",stdin);
//freopen(task".out","w",stdout);
}
cin>>s[0]; n = s[0].size();
s[1] = s[0]; reverse(s[1].begin(),s[1].end());
s[0] = " " + s[0]; s[1] = " " + s[1];
performHash(); pw[0] = 1;
for (ll i = 1;i <= n;i++) pw[i] = (pw[i - 1]*base) % mod;
//debug(IsPalin(1,3));
for (ll i = 1;i <= n;i++)
for (ll j = i;j <= i + 1;j++){
if (j > n || s[0][i] != s[0][j]) continue;
ll l = 1,h = min(i,n - j + 1),m;
while(l <= h){
m = (l + h)/2;
if (IsPalin(i - m + 1,j + m - 1)) l = m + 1;
else h = m - 1;
}
ll rad = h; ans += rad; //cout<<i<<" "<<j<<" "<<rad<<"\n";
have[0][i]++; have[0][i - rad]--;
have[1][j]++; have[1][j + rad]--;
if (i - rad <= 0 || j + rad > n) continue;
l = 0; h = min(i - rad,n - j - rad + 1);
ll x = i - rad,y = j + rad;
while(l <= h){
m = (l + h)/2;
ll kq1 = GetHash(x - m,x - 1,0);
ll kq2 = GetHash(n - y - m + 1,n - y,1);
if (kq1 == kq2) l = m + 1;
else h = m - 1;
}
creat[x][s[0][y] - 'a'] += h + 1;
creat[y][s[0][x] - 'a'] += h + 1;
}
//for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; cout<<"\n";
for (ll i = 2;i <= n;i++) have[1][i] += have[1][i - 1];
//for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; return 0;
for (ll i = 2;i <= n;i++) have[1][i] += have[1][i - 1];
for (ll i = n - 1;i > 0;i--) have[0][i] += have[0][i + 1];
for (ll i = n - 1;i > 0;i--) have[0][i] += have[0][i + 1];
//for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; return 0;
//debug(creat[2][2]);
for (ll i = 1;i <= n;i++){
ll kq = have[0][i + 1] + have[1][i - 1],mx = 0;
for (ll j = 0;j < 26;j++) mx = max(mx,creat[i][j]);
ans = max(ans,kq + mx + 1); //cout<<i<<" "<<kq + mx<<"\n";
}
cout<<ans;
}
/// be confident
Compilation message
palinilap.cpp: In function 'int main()':
palinilap.cpp:41:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
41 | freopen(task".inp","r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
1 ms |
340 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
1492 KB |
Output is correct |
| 2 |
Incorrect |
2 ms |
1492 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
45 ms |
24936 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
