#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define int long long
#define rnd(l, r) uniform_int_distribution<int>(l, r)(rng)
using namespace std;
void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mod = 1e8 + 7, N = 1e6 + 100, inf = 1e9, mod2 = 1e9 + 7;
int pw[N], hsh[N], hsh2[N], pw2[N];
int get(int l, int r){
return (((hsh[r]-hsh[l-1]+mod)%mod)*pw[N - r])%mod;
}
int get2(int l, int r){
return (((hsh2[r]-hsh2[l-1]+mod2)%mod2)*pw2[N - r])%mod2;
}
void solve(){
string s;
cin >> s;
int n = s.size();
s = ' ' + s;
for(int i= 1; i <= n;i++){
hsh[i]=(hsh[i-1]+((s[i]-'a'+1)*pw[i-1])%mod)%mod;
hsh2[i]=(hsh2[i-1]+((s[i]-'a'+1)*pw2[i-1])%mod2)%mod2;
}
vector <int> dp(n + 1, -inf);
dp[0] = 0;
int ans = 1;
int mid = n / 2;
for(int i = 1; i <= mid; i++){
for(int j = 1; j <= i; j++){
swap(i, j);
if(get(n - j + 1,n - i + 1) == get(i, j) && get2(n - j + 1,n - i + 1) == get2(i, j)){
dp[j] = max(dp[i - 1] + 2, dp[j]);
ans = max(dp[j], ans);
swap(i, j);
break;
}
swap(i, j);
}
}
for(int i = 0; i <= (n - 1) / 2; i++){
ans = max(dp[i] + 1, ans);
}
cout << ans << endl;
}
main(){
iostream::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
pw[0]=1;
pw2[0] = 1;
for(int i=1;i<N;i++){
pw[i]=(pw[i-1]*27)%mod;
pw2[i] = (pw2[i - 1] * 31) % mod2;
}
int t;
cin >> t;
while(t--)
solve();
}
/*
* Before implementing the problem:
Do I understand the problem correctly?
Which places are tricky? What do I need to remember to implement them correctly?
Which place is the heaviest by implementation? Can I do it simpler?
Which place is the slowest? Where do I need to be careful about constant factors and where I can choose slower but simpler implementation?
----------------------------------
If not AC:
Did you remember to do everything to handle the tricky places you thought about before?
Is the solution correct?
Do I understand the problem correctly?
----------------------------------
If you have a test on which the solution gives wrong answer:
Is the solution doing what it was supposed to do?
Is the problem in the code or in the idea?
*/
Compilation message
palindromic.cpp:66:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
66 | main(){
| ^~~~
palindromic.cpp: In function 'void fp(std::string)':
palindromic.cpp:15:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:15:70: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
15 | void fp(string name){freopen((name+".in").c_str(),"r",stdin); freopen((name+".out").c_str(),"w",stdout);}
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
8 ms |
17244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
8 ms |
17244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
8 ms |
17244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
8 ms |
17244 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
