제출 #945413

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
945413		amirhoseinfar1385	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	95 ms	16264 KiB

palindromic

#include<bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const long long maxn=1000000+10;
bool check(long long a){
	for(long long i=2;i*i<=a;i++){
		if(a%i==0){
			return 0;
		}
	}
	return 1;
}

long long getav(long long a){
	while(check(a)==0){
		a++;
	}
	return a;
}
long long mod=getav(rng()%100000000+993847562),base=getav(rng()%200+1000),mp[maxn];

void aval(){
	mp[0]=1;
	for(long long i=1;i<maxn;i++){
		mp[i]=1ll*mp[i-1]*base%mod;
	}
}

void solve(){
	string s;
	cin>>s;
	long long n=s.size();
	long long mid=n/2;
	string first,second;
	for(long long i=0;i<mid;i++){
		first.push_back(s[i]);
	}
	for(long long i=mid+(n&1);i<n;i++){
		second.push_back(s[i]);
	}
	long long i=0,j=(long long)second.size()-1;
	long long res=0;
	long long hash1=0,hash2=0;
	long long last=0;
	for(long long asd=0;asd<(long long)first.size();asd++){
		hash1+=mp[i-last]*first[i];
		hash2=hash2*base+second[j];
		hash1%=mod;
		hash2%=mod;
		//cout<<asd<<" "<<first[i]<<" "<<second[j]<<" "<<hash1<<" "<<hash2<<endl;
		if(hash1==hash2){
			res+=2;
			hash1=hash2=0;
			last=i+1;
		}
		i++;
		j--;
	}
	if(hash1!=0||(n&1)){
		res++;
	}
	cout<<res<<"\n";
}
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	//freopen("inp.txt","r",stdin);
	aval();
	long long t;
	cin>>t;
	for(long long asd=0;asd<t;asd++){
		solve();
	}
}

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