Submission #1222171

#	Time	Username	Problem	Language	Result	Execution time	Memory
1222171		otarius	Palindromic Partitions (CEOI17_palindromic)	C++20	0 / 100	7 ms	8256 KiB

palindromic

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

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rngl(chrono::steady_clock::now().time_since_epoch().count());

#define int long long
// #define int unsigned long long

// #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>

const ll mod = 1e9 + 7;
// const ll mod = 998244353;

const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 1e6 + 15;

string s; int n;
ll pwr[maxN], hsh[maxN];
void init() {
    pwr[0] = 1;
    for (int i = 1; i < maxN; i++)
        pwr[i] = (pwr[i - 1] * 31) % mod;
}
void init_hash() {
    for (int i = 1; i <= n; i++)
        hsh[i] = (hsh[i - 1] + (s[i] - 'a') * pwr[i] % mod) % mod;
}
bool check(int l1, int r1, int l2, int r2) {
    ll hsh1 = (hsh[r1] - hsh[l1 - 1] + mod) % mod;
    (hsh1 *= pwr[l2 - l1]) %= mod;
    ll hsh2 = (hsh[r2] - hsh[l2 - 1] + mod) % mod;

    return (hsh1 == hsh2);
}
void solve() {
    cin >> s;
    n = s.size();
    s = " " + s;
    init_hash();

    int ans = 0, i = 1, j = n, si = 1, sj = n; bool f = 0;
    while (i <= j) {
        if (check(si, i, j, sj)) {
            if (i == j) ans++, f = 1; else ans += 2;
            si = i + 1; sj = j - 1;
        } i++; j--;
    } ans += !f;
    cout << ans << '\n';
}
int32_t main() { 
// #ifndef ONLINE_JUDGE
//     freopen("input.txt", "r", stdin);
//     freopen("output.txt", "w", stdout);
// #endif
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    
    init();
    int t = 1;
    cin >> t;
    while (t--) {
        solve();
        // cout << '\n';
    }
    return 0;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 20
• Subtask 3: 0 / 25
• Subtask 4: 0 / 40