Submission #320587

#	Time	Username	Problem	Language	Result	Execution time	Memory
320587		AmShZ	Palindromic Partitions (CEOI17_palindromic)	C++11	100 / 100	691 ms	42612 KiB

palindromic

# include <bits/stdc++.h>
 
/*
// ordered_set 
# include <ext/pb_ds/assoc_container.hpp>
# include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
# define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update> 
*/
 
using namespace std;
 
typedef long long                                        ll;
typedef long double                                      ld;
typedef pair <int, int>                                  pii;
typedef pair <pii, int>                                  ppi;
typedef pair <int, pii>                                  pip;
typedef pair <pii, pii>                                  ppp;
typedef pair <ll, ll>                                    pll;
 
# define A                                               first
# define B                                               second
# define endl                                            '\n'
# define sep                                             ' '
# define all(x)                                          x.begin(), x.end()
# define kill(x)                                         return cout << x << endl, 0
# define SZ(x)                                           int(x.size())
# define lc                                              id << 1
# define rc                                              id << 1 | 1
# define InTheNameOfGod                                  ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
 
ll power(ll a, ll b, ll md) {return (!b ? 1 : (b & 1 ? a * power(a * a % md, b / 2, md) % md : power(a * a % md, b / 2, md) % md));}
 
const int xn = 1e6 + 10;
const int xm = - 20 + 10;
const int sq = 320;
const int inf = 1e9 + 10;
const ll INF = 1e18 + 10;
const int mod[3] = {998244353, 1000000007, 1000000009};
const int base = 257;

int n, pw[3][xn], Hash[3][xn], inv[3][xn], Inv[3], ans, q;
string s;

void build(){
	for (int i = 0; i < 3; ++ i)
		pw[i][0] = inv[i][0] = 1, Inv[i] = power(base, mod[i] - 2, mod[i]);
	for (int i = 0; i < 3; ++ i){
		for (int j = 1; j < xn; ++ j){
			pw[i][j] = ll(pw[i][j - 1]) * ll(base) % mod[i];
			inv[i][j] = ll(inv[i][j - 1]) * ll(Inv[i]) % mod[i];
		}
	}
}
void build_query(){
	for (int i = 0; i < 3; ++ i)
		for (int j = 1; j <= n; ++ j)
			Hash[i][j] = (ll(Hash[i][j - 1]) + ll(s[j] - 'a') * ll(pw[i][j]) % mod[i]) % mod[i];
}
int get(int l, int r, int ind){
	return (ll(Hash[ind][r]) - ll(Hash[ind][l - 1]) + ll(mod[ind])) * ll(inv[ind][l - 1]) % mod[ind];
}
bool check(int l1, int r1, int l2, int r2){
	bool flag = true;
	for (int i = 0; i < 3; ++ i)
		flag &= get(l1, r1, i) == get(l2, r2, i);
	return flag;
}
void solve(){
	cin >> s;
	n = SZ(s);
	s = '.' + s;
	build_query();
	ans = 0;
	int l = 1, r = 1;
	while (true){
		int l2 = n - r + 1;
		int r2 = n - l + 1;
		if (l2 <= r)
			break;
		if (!check(l, r, l2, r2)){
			++ r;
			continue;
		}
		ans += 2;
		++ r;
		l = r;
		if (n % 2 == 0 && r == n / 2 + 1)
			-- ans;
	}
	++ ans;
	cout << ans << endl;
}

int main(){
	InTheNameOfGod;
	
	build();
	cin >> q;
	while (q --)
		solve();
	
	return 0;
}

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