Submission #563250

#	Time	Username	Problem	Language	Result	Execution time	Memory
563250		kawaii	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	1284 ms	20776 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define fi first
#define se second
#define hash hsh

int t, n, m, k, hash[1000005], base = 353, mod = 696969601;
string s;
mt19937_64 rng;

int mul(int x, int y){
    if(y == 0) return 1;
    int ans = mul(x, y / 2);
    if(y % 2 == 0) return (ans * ans) % mod;
    else return (((ans * ans) % mod) * x) % mod;
}

void solve(){
    n = s.size();
    s = '0' + s;
    for(int i = 1; i <= n; i++) hash[i] = (hash[i - 1] * base + s[i]) % mod; 
    int cnt = 1, ans = 0;
    while(cnt <= n - cnt + 1){ 
        int f = cnt;
        bool flag = 0;
        while(1){
            int num1 = (hash[cnt] - (hash[f - 1] * mul(base, cnt - f + 1)) % mod) % mod;
            int num2 = (hash[n - f + 1] - (hash[n - cnt] * mul(base, cnt - f + 1)) % mod) % mod;
            // cout << cnt <<" "<< n - cnt + 1 <<" "<< num1 <<" "<< num2 <<" "<< ans << endl;
            if((num1 + mod) % mod == (num2 + mod) % mod){
                if(cnt == n - cnt + 1) ans++;
                else ans += 2; 
                cnt++; flag = 1; break;
            }
            cnt++;
            if(cnt > n - cnt + 1) break;
        }
        if(!flag){
            ans++; break;
        } 
    }
    cout << ans << "\n";
}

signed main(){
    ios_base::sync_with_stdio(NULL); cin.tie(nullptr); cout.tie(nullptr);
    // rng.seed((int)main ^ time(0));
    #ifdef Kawaii
        auto starttime = chrono::high_resolution_clock::now();
    #endif

    cin >> t;
    while(t--){
        cin >> s;
        solve();
    }

    #ifdef Kawaii
        auto endtime = chrono::high_resolution_clock::now();
        auto duration = chrono::duration_cast<chrono::milliseconds>(endtime - starttime).count(); 
        cout << "\n=====" << "\nUsed: " << duration << " ms\n";
    #endif
}

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