제출 #629213

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
629213		ddy888	Palindromic Partitions (CEOI17_palindromic)	C++17	0 / 100	7 ms	8148 KiB

palindromic

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("unroll-loops")
using namespace std;
using namespace __gnu_pbds;

using ll = long long;
#define pb push_back
#define fi first
#define si second
#define ar array
typedef pair<int,int> pi;
typedef tuple<int,int,int> ti;  
template<typename T> bool chmin(T &a, T b){return (b < a) ? a = b, 1 : 0;}
template<typename T> bool chmax(T &a, T b){return (b > a) ? a = b, 1 : 0;}
template<class key, class value = null_type, class cmp = less<key> >
using ordered_set = tree<key, value, cmp, rb_tree_tag, tree_order_statistics_node_update>;
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

void debug_out() {cerr<<endl;}
template <typename Head, typename... Tail>
void debug_out(Head _H, Tail... _T) {cerr<<" "<<to_string(_H);debug_out(_T...);}
#define debug(...) cerr<<"["<<#__VA_ARGS__<<"]:",debug_out(__VA_ARGS__)
const int MAXN = 1000010, MOD = 1e9+9, P = 31;

int n;
string s;
ll pref[MAXN], power[MAXN];

ll value(int i, int j) {
    if (i == 0) return pref[j];
    return ((pref[j]-(pref[i-1]*power[j-i+1])%MOD)%MOD+MOD)%MOD;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    cin.exceptions(ios::badbit | ios::failbit);
    power[0] = 1;
    for (int i = 1; i < MAXN; ++i) {
        power[i] = power[i-1] * P;
        power[i] %= MOD;
    }
    int tests; cin >> tests;
    while (tests--) {
        cin >> s;
        n = s.size();
        pref[0] = s[0]-'a'+1;
        for (int i = 1; i < n; ++i) {
            pref[i] = (pref[i-1]*P)%MOD + (s[i]-'a'+1);
            pref[i] %= MOD;
        }
        int lx = 0, rx = n-1, j = n-1;
        int ans = 0;
        for (int i = 0; i < n; ++i) {
            if (j <= i) break;
            if (value(lx, i) == value(j, rx)) {
                ans += 2;
                lx = i+1, rx = j-1;
            }
            --j;
        }
        cout << ans + (s[j] != s[j+1]) << '\n';
    }
    return 0;
} 

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