Submission #585635

#	Time	Username	Problem	Language	Result	Execution time	Memory
585635		amunduzbaev	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	140 ms	11708 KiB

palindromic

#include "bits/stdc++.h"
using namespace std;
 
#define ar array
typedef int64_t ll;


const int N = 1e4 + 5;
const int P = 167;
const int mod = 1e9 + 7;

void solve(){
	string s; cin >> s;
	int n = s.size();
	s = "#" + s;
	int h[n + 1] {}, pw[n + 1];
	pw[0] = 1;
	for(int i=1;i<=n;i++){
		h[i] = (h[i - 1] * 1ll * P + s[i] - 'a') % mod;
		pw[i] = pw[i - 1] * 1ll * P % mod;
	}
	
	auto check = [&](int l, int r){ l--;
		return (h[r] - h[l] * 1ll * pw[r - l] % mod + mod) % mod == 
		(h[n - l] - h[n - r] * 1ll * pw[r - l] % mod + mod) % mod;
	};
	
	int res = 0, last = 1;
	for(int i=1;i<=n/2;i++){
		if(check(last, i)){
			//~ cout<<last<<" "<<i<<"\n";
			res += 2;
			last = i + 1;
		}
	}
	
	if(n & 1) res++;
	else if(last <= n / 2) res++;
	
	cout<<res<<"\n";
}

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int t; cin>>t;
	while(t--){
		solve();
	}
}

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