Submission #1165462

#	Time	Username	Problem	Language	Result	Execution time	Memory
1165462		MPG	Palindromic Partitions (CEOI17_palindromic)	C++20	100 / 100	339 ms	27440 KiB

palindromic

//#pragma GCC optomize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
//#pragma GCC target("sse,sse2,sse4.1,sse4.2") 



#include <bits/stdc++.h>
using namespace std;
typedef long long       ll;
#define     max_heap priority_queue<pair <ll, pair <ll, ll>>>
#define     min_heap priority_queue<pair <ll, ll>, vector<pair <ll, ll>>, greater<pair <ll, ll>>>
#define     sariE cin.tie(NULL); cout.tie(NULL); ios_base::sync_with_stdio(false);
#define     filE freopen("in.txt", "r", stdin);// freopen("out1.txt", "w", stdout); 
#define     endl '\n'
#define     md(a) (a % mod + mod) % mod
#define     pb push_back
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
//cout << setprecision(5) << fixed << f;
//hash prime = 769


ll const maxn = 1e6 + 123;
ll const inf = 3e18;
ll const loG = 18; // 23
ll const mod = 1e9 + 7;
//ll const mod = 998244353;
ll const sq = 500;
ll power(ll a, ll b, ll mod){if(b==0)return 1;if(b==1)return a;ll x = power(a, b / 2, mod);return (((x * x) % mod) * (b % 2 ? a : 1)) % mod;}


ll p = 769;
ll n, ps[maxn], tav[maxn], inv[maxn];
string s;

ll get(ll l, ll r){
    ll ret = md(ps[r] - ps[l - 1]);
    ret = ret * inv[l - 1] % mod;
    return ret;
}


void Solve(){

cin >> s;
n = s.size();
s = ' ' + s;
for (int i = 1; i < n + 1; i++){
    ps[i] = (ps[i - 1] + (s[i] - 'a' + 1) * tav[i] % mod) % mod;
}
ll ans = 0, ind = 0, last = n + 1;
bool ok = 1;
while (ok){
    ok = 0; 
    ind++;
    if (ind >= last){
        break;
    }
    //cout << "started " << ind << ' ' << last << endl;
    for (int i = ind, cnt = 1; i < last; i++, cnt++){
        ll x = get(ind, i), y = get(last - cnt, last - 1);
        //cout << i << ' ' << x << ' ' << y << endl;
        if (i >= last - cnt)
            break;
        if (x == y){
            ok = 1;
            ind = i;
            last = last - cnt;
            ans += 2;
            break;
        }
    }
    if (!ok)
        ans++;
}
cout << ans << endl;

}



int main(){
sariE;
//filE;


tav[0] = 1;
inv[0] = 1;
for (int i = 1; i < maxn; i++){
    tav[i] = (tav[i - 1] * p) % mod;
    inv[i] = power(tav[i], mod - 2, mod);
}


int test = 1;
cin >> test;
while (test--) Solve();
return 0;
}

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