Submission #1089877

#	Time	Username	Problem	Language	Result	Execution time	Memory
1089877		alexdumitru	Palindromic Partitions (CEOI17_palindromic)	C++17	100 / 100	120 ms	26816 KiB

palindromic

#include <iostream>
#include <vector>

std::string s;
int n;

namespace Hash {
    std::vector<long long> sp;
    std::vector<long long> pBase;
    const int MOD = 1e9 + 7;
    const int BASE = 29;

    void init() {
        sp.resize(n + 1);
        pBase.resize(n + 1);
        sp[0] = 0;
        pBase[0] = 1;
        for (int i = 1; i <= n; i++) {
            pBase[i] = pBase[i - 1] * BASE % MOD;
            sp[i] = (sp[i - 1] * BASE + s[i - 1] - 'a') % MOD;
        }
    }

    int get_hash(int l, int r) {
        return ((sp[r + 1] - sp[l] * pBase[r - l + 1]) % MOD + MOD) % MOD;
    }
}

void read() {
    std::cin >> s;
    n = s.length();
}

void solve() {
    int l = 0, r = n - 1;
    int ans = 0;

    while (l <= r) {
        ans++;
        int sz = r - l + 1;
        int lim = sz >> 1;
        int lgmin = sz;
        for (int lg = 1; lg <= lim; lg++) {
            if (Hash::get_hash(l, l + lg - 1) == Hash::get_hash(r - lg + 1, r)) {
                lgmin = lg;
                ans++;
                break;
            }
        }
        l += lgmin;
        r -= lgmin;
    }

    std::cout << ans << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int t;
    std::cin >> t;
    while (t--) {
        read();
        Hash::init();
        solve();
    }

    return 0;
}

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