제출 #856358

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
856358		Cyanmond	Palindromic Partitions (CEOI17_palindromic)	C++17	0 / 100	0 ms	348 KiB

palindromic

#include <bits/stdc++.h>

using namespace std;

#define rep(i, l, r) for (int i = (l); i < (r); ++i)
#define per(i, l, r) for (int i = (r - 1); i >= l; --i)
#define ALL(x) (x).begin(), (x).end()

using i64 = long long;

using u64 = unsigned long long;
constexpr u64 mod = (1ull << 61) - 1;
constexpr u64 base = 1000000007;

u64 safeMod(u64 v) {
    if (v < 0) v += mod;
    return v % mod;
}

struct SH {
    static constexpr u64 mul(u64 a, u64 b) {
        __uint128_t x = (__uint128_t)(a) * (__uint128_t)(b);
        return x % mod;
    }

    int n;
    string S;
    vector<u64> hash;

    SH(string s) : S(s) {
        n = (int)S.size();
        hash.assign(n + 1, 0);
        rep(i, 0, n) {
            hash[i + 1] = (mul(hash[i], base) + (u64)(S[i] - 'a')) % mod;
        }
    }
};

void main_() {
    string S;
    cin >> S;
    const int N = (int)S.size();
    string A = S.substr(0, N / 2), B = S.substr(N - N / 2, N / 2);
    const int M = (int)A.size();
    vector<u64> baseTable(M + 10);
    baseTable[0] = 1;
    rep(i, 1, M + 10) baseTable[i] = SH::mul(baseTable[i - 1], base);

    SH ha(A), hb(B);

    auto judge = [&](int l, int r) {
        u64 hs1 = safeMod(ha.hash[r] - SH::mul(ha.hash[l], baseTable[r - l]));
        u64 hs2 = safeMod(hb.hash[M - l] - SH::mul(hb.hash[M - r], baseTable[r - l]));
        return hs1 == hs2;
    };

    int l = 0, r = 0;
    int ans = 0;
    while (true) {
        if (r == M) {
            cout << ans + N % 2 << endl;
            return;
        }
        while (not judge(l, r + 1)) {
            ++r;
            if (r == M) {
                cout << ans + 1 << endl;
                return;
            }
        }
        l = l + 1;
        r = r + 1;
        ans += 2;
    }
    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T;
    cin >> T;
    while (T--) main_();
}

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