Submission #868408

#	Time	Username	Problem	Language	Result	Execution time	Memory
868408		themm1	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	53 ms	19136 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
// ordered set whith s.order_of_key(x) method, which returns rank of element x in set s
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
*/

// pair printing
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "(" << par.first << "; " << par.second << ")"; return out;}
// set printing
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for(const auto &x:cont) out << x << ", "; out << "}"; return out; }
// map printing
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for(const auto &x:cont) out << x << ", "; out << "}"; return out; }
// unordered_set printing
template <class T>
ostream& operator<<(ostream& out, const unordered_set<T> &cont) {out << "{";for(const auto &x:cont) out << x << ", ";out << "}";return out;}
// unordered_map printing
template <class T, class U>
ostream& operator<<(ostream& out, const unordered_map<T, U> &cont) {out << "{";for(const auto &x:cont) out << x << ", ";out << "}";return out;}
// vector printing
template<class T>
ostream& operator<<(ostream& out, const vector<T> &cont){ out << "[";  for (const auto &x:cont) out << x << ", ";  out << "]"; return out;}

#define print(x) cout << (x) << endl;
#define dmp(x) cerr << #x << " = " << x << endl
#define dmpn(x) cerr << #x << " = " << x << "; "
#define dmpl(x) cerr << "Line " << __LINE__ << ": " << #x << " = " << x << endl

#define int long long
using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define pb push_back
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define sz(x) (int)x.size()
#define contains(s,x) ((s).find(x) != (s).end())
const int MOD = 998244353;
const int SZ = 26;

int N;
string s;
vector<int> pows;

pii cut(int l, int r) {
        int front_hsh = 0, back_hsh = 0;
        for (int i = l, j = r; i < j; i++, j--) {
                front_hsh = (front_hsh + (s[i] * pows[i - l]) % MOD) % MOD;
                int back_i = N - (r - j);
                back_hsh = (back_hsh + (s[j] * pows[back_i]) % MOD) % MOD;
                
                int shifted_fhsh = (front_hsh * pows[back_i]) % MOD;
                if (shifted_fhsh == back_hsh) {
                        return { i + 1, j - 1 };
                }
        }
        return { -INT_MAX, -INT_MAX };
}

void solve() {
        cin >> s;
        N = sz(s);
        int l = 0, r = N - 1, ans = 0;
        while (l < r) {
                pii p = cut(l, r);
                l = p.ff;
                r = p.ss;
                if (l == -INT_MAX) break;
                ans += 2;
        }
        if (l == r) ans++;
        cout << ans << endl;
}

int32_t main() {
        pows.assign(1e6 + 10, 1);
        for (int i = 1; i < 1e6 + 10; i++) pows[i] = (pows[i - 1] * SZ) % MOD;

        ios::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);

        int t = 1;
        cin >> t;
        while (t--) {
                solve();
        }
}

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