Submission #667183

#	Time	Username	Problem	Language	Result	Execution time	Memory
667183		Shahrad	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	108 ms	28524 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ld long double
#define endl '\n'
#define pb push_back
#define mk make_pair
#define sz size()
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define kill(x) return cout << x << endl, void();
#define int ll
#define pii pair <int, int>

#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target ("avx2")

const int N = 1e6 + 5;
const int MOD = 998244353, INF = 2e9, sq = 450;

int ps[N], pw[N];
int mab = 27;

int hsh (int l, int r)
{
	return (ps[r] - (l == 0 ? 0 : ps[l - 1]) * pw[r - l + 1] % MOD + MOD) % MOD;
}

void Solve ()
{
	string s;
	cin >> s;
	int n = s.sz, l = 0, ans = 0;
	ps[0] = s[0] - 'a' + 1;
	for (int i = 1; i < n; i++)
			ps[i] = (ps[i - 1] * mab + (s[i] - 'a' + 1)) % MOD;
	for (int r = l; r < n - l; r++)
	{
		if (hsh (l, r) == hsh (n - r - 1, n - l - 1))
		{
			ans += 2;
			if (r == n - l - 1)
				ans--;
			l = r + 1;
		}
	}
	cout << ans << endl;
}

int32_t main ()
{
	pw[0] = 1;
	for (int i = 1; i < N; i++)
		pw[i] = pw[i - 1] * mab % MOD;
	ios::sync_with_stdio (0), cin.tie (0), cout.tie (0);
	int tt = 1;
	cin >> tt;
	while (tt--)
		Solve ();
}

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