結果

問題 No.2048 L(I+D)S
コンテスト
ユーザー Mihnea-Vicențiu
提出日時 2025-01-02 05:51:45
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 31 ms / 2,000 ms
コード長 5,506 bytes
コンパイル時間 3,918 ms
コンパイル使用メモリ 311,912 KB
実行使用メモリ 11,464 KB
最終ジャッジ日時 2025-01-02 05:51:52
合計ジャッジ時間 5,321 ms
ジャッジサーバーID
（参考情報） 		judge4 / 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 * 16
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>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

#define ar array
#define vt vector
#define pq priority_queue
#define pu push
#define pub push_back
#define em emplace
#define emb emplace_back
#define mt make_tuple

#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define allp(x, l, r) x.begin() + l, x.begin() + r
#define len(x) (int)x.size()
#define uniq(x) unique(all(x)), x.end()

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template <class T, size_t N>
void re(array <T, N>& x);
template <class T> 
void re(vt <T>& x);

template <class T> 
void re(T& x) {
    cin >> x;
}

template <class T, class... M> 
void re(T& x, M&... args) {
    re(x), re(args...);
}

template <class T> 
void re(vt <T>& x) {
    for(auto& it : x) re(it);
}

template <class T, size_t N>
void re(array <T, N>& x) {
    for(auto& it : x) re(it);
}

template <class T, size_t N>
void wr(const array <T, N>& x);
template <class T> 
void wr(const vt <T>& x);

template <class T> 
void wr(const T& x) {
    cout << x;
}

template <class T, class ...M>  
void wr(const T& x, const M&... args) {
    wr(x), wr(args...);
}

template <class T> 
void wr(const vt <T>& x) {
    for(auto it : x) wr(it, ' ');
}

template <class T, size_t N>
void wr(const array <T, N>& x) {
    for(auto it : x) wr(it, ' ');
}

template<class T, class... M>
auto mvt(size_t n, M&&... args) {
    if constexpr(sizeof...(args) == 1)
        return vector<T>(n, args...);
    else
        return vector(n, mvt<T>(args...));
}

void set_fixed(int p = 0) {
    cout << fixed << setprecision(p);
}

void set_scientific() {
    cout << scientific;
}

void Open(const string& name) {
#ifndef ONLINE_JUDGE
    (void)!freopen((name + ".in").c_str(), "r", stdin);
    (void)!freopen((name + ".out").c_str(), "w", stdout);
#endif
}

const int mod = 998'244'353;

template <unsigned MOD> struct modint {
    using M = modint;

    unsigned x;
    modint(ll x = 0) { fix(x % MOD + MOD); }

    inline M& fix(unsigned _x) {
        x = (_x < MOD)? _x : _x - MOD;
        return *this;
    }

    explicit operator bool() const { return x != 0; }
    explicit operator long long() const { return x; } 
    
    inline bool operator == (const M& other) const { return x == other.x; }
    inline bool operator != (const M& other) const { return x != other.x; }
    inline bool operator <  (const M& other) const { return x <  other.x; }
    inline bool operator >  (const M& other) const { return x >  other.x; }
    inline bool operator <= (const M& other) const { return x <= other.x; }
    inline bool operator >= (const M& other) const { return x >= other.x; }

    inline M operator  + () const { return M().fix(x); }
    inline M operator  - () const { return M().fix(MOD - x); }
    inline M& operator ++ ()       { this-> fix(x + 1); return *this; } 
    inline M  operator ++ (int)    { M tmp(*this); ++(*this); return tmp; }
    inline M& operator -- ()       { this-> fix(x - 1 + MOD); return *this; }
    inline M  operator -- (int)    { M tmp(*this); --(*this); return tmp; }

    inline M operator + (const M& other) const { return M().fix(x + other.x); }
    inline M operator - (const M& other) const { return M().fix(x + MOD - other.x); }     
    inline M operator * (const M& other) const { return M().fix((ull)x * other.x % MOD); } 
    inline M operator / (const M& other) const { return *this * other.inv(); }

    inline M& operator += (const M& other) { return *this = *this + other; }
    inline M& operator -= (const M& other) { return *this = *this - other; }
    inline M& operator *= (const M& other) { return *this = *this * other; } 
    inline M& operator /= (const M& other) { return *this = *this / other; } 

    M lgput(ll b) const {
        M a = *this, res = 1; 
        while (b) {
            if (b & 1) res *= a; 
            a *= a;
            b >>= 1;
        }
        return res;
    }

    M inv() const { return lgput(MOD - 2); }

    friend M operator + (const ll&  value, const M& n) { return n + M(value); }
    friend M operator + (const int& value, const M& n) { return n + M(value); }
    friend M operator - (const ll&  value, const M& n) { return n - M(value); }
    friend M operator - (const int& value, const M& n) { return n - M(value); }
    friend M operator * (const ll&  value, const M& n) { return n * M(value); }
    friend M operator * (const int& value, const M& n) { return n * M(value); }

    friend istream& operator >> (istream& in, M& n) { ll x; in >> x; n = x; return in; }
    friend ostream& operator << (ostream& os, const M& n) { return os << n.x; }
};

using mint = modint<mod>;


const int N = 1e6 + 1;
mint fact[N], ifact[N];

void prec() {
    fact[0] = ifact[0] = 1;
    fact[1] = ifact[1] = 1;
    for (int i = 2; i < N; ++i)
        fact[i] = fact[i - 1] * i;

    ifact[N - 1] = fact[N - 1].inv();
    for (int i = N - 2; i >= 2; --i)
        ifact[i] = ifact[i + 1] * (i + 1);
}

void solve() {
    int n; re(n);
    mint res = 0;
    for (int a = 2; a <= n; ++a) {
        int b = n - a;
        mint f_lambda = fact[a + b] / (fact[a - 2] * fact[b - 2] * (a + b - 1) * a * b);
        res += f_lambda * f_lambda;
    }
    wr(res, '\n');
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    //Open("");

    prec();

    int t = 1;
    for(;t;t--) {
        solve();
    }
    
    return 0;
}
0