結果

問題 No.2717 Sum of Subarray of Subsequence
ユーザー Today03
提出日時 2024-04-05 22:38:42
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 160 ms / 2,000 ms
コード長 3,381 bytes
コンパイル時間 2,352 ms
コンパイル使用メモリ 197,336 KB
最終ジャッジ日時 2025-02-20 21:50:38
ジャッジサーバーID
（参考情報） 		judge2 / judge2
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 3
other AC * 21
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

template <ll MOD>
struct modint {
    ll value;
    modint(ll x = 0) {
        if (x >= 0) {
            value = x % MOD;
        } else {
            value = MOD - (-x) % MOD;
        }
    }
    modint operator-() const {
        return modint(-value);
    }
    modint operator+() const {
        return modint(*this);
    }
    modint &operator+=(const modint &other) {
        value += other.value;
        if (value >= MOD) {
            value -= MOD;
        }
        return *this;
    }
    modint &operator-=(const modint &other) {
        value += MOD - other.value;
        if (value >= MOD) {
            value -= MOD;
        }
        return *this;
    }
    modint &operator*=(const modint other) {
        value = value * other.value % MOD;
        return *this;
    }
    modint &operator/=(modint other) {
        (*this) *= other.inv();
        return *this;
    }
    modint operator+(const modint &other) const {
        return modint(*this) += other;
    }
    modint operator-(const modint &other) const {
        return modint(*this) -= other;
    }
    modint operator*(const modint &other) const {
        return modint(*this) *= other;
    }
    modint operator/(const modint &other) const {
        return modint(*this) /= other;
    }
    modint pow(ll x) const {
        modint ret(1), mul(value);
        while (x) {
            if (x & 1) {
                ret *= mul;
            }
            mul *= mul;
            x >>= 1;
        }
        return ret;
    }
    modint inv() const {
        return pow(MOD - 2);
    }
    bool operator==(const modint &other) const {
        return value == other.value;
    }
    bool operator!=(const modint &other) const {
        return value != other.value;
    }
    friend ostream &operator<<(ostream &os, const modint &x) {
        return os << x.value;
    }
    friend istream &operator>>(istream &is, modint &x) {
        ll v;
        is >> v;
        x = modint<MOD>(v);
        return is;
    }
};
using mod998 = modint<998244353>;
using mod107 = modint<1000000007>;

template <typename T>
struct combination {
    vector<T> fact, factinv;
    combination(int n) {
        fact = vector<T>(n + 1);
        factinv = vector<T>(n + 1);
        fact[0] = 1;
        for (int i = 1; i <= n; i++) {
            fact[i] = fact[i - 1] * i;
        }
        for (int i = 0; i <= n; i++) {
            factinv[i] = fact[i].inv();
        }
    }
    T nCr(ll n, ll r) {
        if (n < 0 || r < 0 || n - r < 0) {
            return 0;
        }
        return fact[n] * factinv[r] * factinv[n - r];
    }
    T nPr(ll n, ll r) {
        if (n < 0 || r < 0 || n - r < 0) {
            return 0;
        }
        return fact[n] * factinv[n - r];
    }
};

using mint = mod998;

int main() {
    int N;
    cin >> N;
    vector<mint> A(N);
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }
    combination<mint> C(N);

    auto F = [&](int n) {
        if (n == 0) {
            return mint(1);
        }
        return mint(2).pow(n - 1) * (n + 2);
    };

    vector<mint> cnt(N);
    for (int i = 0; i < N; i++) {
        cnt[i] = F(N - i - 1) * F(i);
    }

    mint ans = 0;
    for (int i = 0; i < N; i++) {
        ans += cnt[i] * A[i];
    }

    cout << ans << endl;
}
0