Submission #955649

#	Time	Username	Problem	Language	Result	Execution time	Memory
955649		thunopro	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	130 ms	11624 KiB

palindromic

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 1000009 
#define ll long long 
#define fi first 
#define se second 
#define pb push_back 
#define left id<<1
#define right id<<1|1 
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1 
#define TIME (1.0*clock()/TIME_PERS_SEC) 
#define re exit(0); 

const int mod = 1e9+7 ; 
const int INF = 1e9 ; 

typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 

void add ( int &a , int b ) 
{
	a += b ; 
	if ( a >= mod ) a -= mod ; 
	if ( a < 0 ) a += mod ; 
}

template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ;} 
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ;} 

void rf () 
{
	freopen ("bai1.inp","r",stdin) ; 
}

int _pow ( int a , int n ) 
{
	if ( n == 0 ) return 1 ; 
	int res = _pow (a,n/2) ; 
	if ( n % 2 ) return 1ll*res*res%mod*a%mod ; 
	else return 1ll*res*res%mod ; 
}

mt19937 rng(time(0)) ; 

string s ;
int hashA [maxn] ; 
int Pow [maxn] ; 

int get_hashA ( int l , int r ) 
{
	return (hashA[r]-1ll*hashA[l-1]*Pow[r-l+1]%mod+1ll*mod*mod)%mod ; 
}
int solve ( int l , int r ) 
{
	if ( l == r ) return 1 ; 
	if ( l > r ) return 0 ; 
	for ( int i = 0 ; l+i < r-i ; i ++ ) 
	{
		if ( get_hashA (l,l+i) == get_hashA (r-i,r) ) return 2 + solve (l+i+1,r-i-1) ; 
	}
	return 1 ; 
}

int main ()
{
	ios_base::sync_with_stdio(0); 
	cin.tie(0);cout.tie(0); 
//	rf () ; 
	Pow [0] = 1 ; 
	for ( int i = 1 ; i < maxn ; i ++ ) Pow [i] = 1ll*Pow[i-1]*53%mod ; 
	int test ; cin >> test ; 
	while ( test -- ) 
	{
		cin >> s ;
		int n = s.size () ; 
		s = ' ' + s ; 
		for ( int i = 1 ; i <= n ; i ++ ) hashA [i] = (1ll*hashA[i-1]*53+s[i])%mod ; 
		cout << solve (1,n) << "\n" ; 
	}
}

Compilation message (stderr)

palindromic.cpp: In function 'void rf()':
palindromic.cpp:33:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40