제출 #645088

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
645088		ghostwriter	Palindromic Partitions (CEOI17_palindromic)	C++14	100 / 100	241 ms	28888 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const pi M = {1e9 + 7, 1e9 + 9};
const pi base = {37, 127};
const int N = 1e6 + 5;
int t, n;
pi H[N], P[N];
str s;
pi get(int l, int r) {
    pi ans;
    ans.st = (H[r].st - 1LL * H[l - 1].st * P[r - l + 1].st % M.st + M.st) % M.st;
    ans.nd = (H[r].nd - 1LL * H[l - 1].nd * P[r - l + 1].nd % M.nd + M.nd) % M.nd;
    return ans;
}
void solve() {
	cin >> s;
	n = sz(s);
	s = "#" + s + "#";
    P[0] = {1, 1};
	FOR(i, 1, n) {
        P[i].st = 1LL * P[i - 1].st * base.st % M.st;
        P[i].nd = 1LL * P[i - 1].nd * base.nd % M.nd;
        H[i].st = (1LL * H[i - 1].st * base.st % M.st + s[i] - 'a' + 1) % M.st;
        H[i].nd = (1LL * H[i - 1].nd * base.nd % M.nd + s[i] - 'a' + 1) % M.nd;
    }
    int l = 1, r = n, rs = 0;
    WHILE(l <= r) {
        int pos = 0;
        int mid = (l + r) / 2 - ((r - l + 1) & 1? 1 : 0);
        FOR(i, l, mid) {
            int len = i - l + 1;
            pi left = get(l, i), right = get(r - len + 1, r);
            if (left == right) {
                pos = i;
                break;
            }
        }
        if (!pos) {
            ++rs;
            break;
        }
        rs += 2;
        int len = pos - l + 1;
        l += len;
        r -= len;
    }
    cout << rs << '\n';
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    cin >> t;
    WHILE(t--) solve();
    return 0;
}
/*
4
bonobo
deleted
racecar
racecars
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

컴파일 시 표준 에러 (stderr) 메시지

palindromic.cpp: In function 'void solve()':
palindromic.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
palindromic.cpp:66:2: note: in expansion of macro 'FOR'
   66 |  FOR(i, 1, n) {
      |  ^~~
palindromic.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
palindromic.cpp:76:9: note: in expansion of macro 'FOR'
   76 |         FOR(i, l, mid) {
      |         ^~~

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