結果

問題 No.1191 数え上げを愛したい（数列編）
ユーザー minatominato
提出日時 2020-08-25 08:07:47
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 13 ms / 2,000 ms
コード長 4,104 bytes
コンパイル時間 4,156 ms
コンパイル使用メモリ 238,724 KB
実行使用メモリ 11,220 KB
最終ジャッジ日時 2024-11-06 11:02:55
合計ジャッジ時間 5,361 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 11 ms
11,012 KB
testcase_01 AC 12 ms
11,052 KB
testcase_02 AC 11 ms
11,008 KB
testcase_03 AC 11 ms
10,988 KB
testcase_04 AC 11 ms
11,012 KB
testcase_05 AC 10 ms
10,980 KB
testcase_06 AC 13 ms
11,056 KB
testcase_07 AC 10 ms
11,220 KB
testcase_08 AC 10 ms
11,016 KB
testcase_09 AC 12 ms
10,992 KB
testcase_10 AC 11 ms
10,984 KB
testcase_11 AC 11 ms
11,032 KB
testcase_12 AC 11 ms
11,080 KB
testcase_13 AC 11 ms
11,048 KB
testcase_14 AC 12 ms
11,012 KB
testcase_15 AC 10 ms
11,052 KB
testcase_16 AC 11 ms
11,044 KB
testcase_17 AC 10 ms
10,892 KB
testcase_18 AC 11 ms
10,864 KB
testcase_19 AC 11 ms
10,860 KB
testcase_20 AC 10 ms
11,020 KB
testcase_21 AC 10 ms
11,144 KB
testcase_22 AC 11 ms
10,928 KB
testcase_23 AC 10 ms
10,892 KB
testcase_24 AC 10 ms
11,152 KB
testcase_25 AC 11 ms
10,992 KB
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 # 

#pragma GCC optimize("Ofast")
#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;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<long long, long long>;
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()
constexpr char ln = '\n';
//constexpr long long MOD = 1000000007;
constexpr long long MOD = 998244353;
template<class T1, class T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return true;} return false; }
template<class T1, class T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return true;} return false; }
inline int popcount(int x) {return __builtin_popcount(x);}
inline int popcount(long long x) {return __builtin_popcountll(x);}
void print() { cout << "\n"; }
template<class T, class... Args>
void print(const T &x, const Args &... args) {
    cout << x << " ";
    print(args...);
}
///////////////////////////////////////////////////////////////////////////////////////////////////////////////

template <uint_fast64_t Modulus> 
struct ModInt {
    using u64 = uint_fast64_t;

    u64 a;

    constexpr ModInt(const long long x = 0) noexcept : a(x >= 0 ? x % Modulus : (Modulus - (-x) % Modulus) % Modulus) {}
    constexpr u64 &value() noexcept {return a;}
    constexpr const u64 &value() const noexcept {return a;}
    constexpr ModInt operator+(const ModInt rhs) const noexcept {return ModInt(*this) += rhs;}
    constexpr ModInt operator-(const ModInt rhs) const noexcept {return ModInt(*this) -= rhs;}
    constexpr ModInt operator*(const ModInt rhs) const noexcept {return ModInt(*this) *= rhs;}
    constexpr ModInt operator/(const ModInt rhs) const noexcept {return ModInt(*this) /= rhs;}
    constexpr ModInt operator^(const long long rhs) const noexcept {return ModInt(*this) ^= rhs;}
    constexpr bool operator==(const ModInt &rhs) const noexcept {return a == rhs.a;}
    constexpr bool operator!=(const ModInt &rhs) const noexcept {return a != rhs.a;}
    constexpr ModInt &operator+=(const ModInt rhs) noexcept {
        a += rhs.a;
        if (a >= Modulus) {
            a -= Modulus;
        }
        return *this;
    }
    constexpr ModInt &operator-=(const ModInt rhs) noexcept {
        if (a < rhs.a) {
            a += Modulus;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr ModInt &operator*=(const ModInt rhs) noexcept {
        a = a * rhs.a % Modulus;
        return *this;
    }
    constexpr ModInt &operator/=(ModInt rhs) noexcept {
        u64 exp = Modulus - 2;
        while (exp) {
            if (exp&1) *this *= rhs;
            exp >>= 1;
            rhs *= rhs;
        }
        return *this;
    }
    constexpr ModInt &operator^=(long long exp) noexcept {
        ModInt rhs = a;
        a = 1;
        while (exp) {
            if (exp&1) *this *= rhs;
            exp >>= 1;
            rhs *= rhs;
        }
        return *this;
    }

    friend ostream &operator<<(ostream& os, const ModInt& rhs) noexcept {return os << rhs.a;}
    friend istream &operator>>(istream& is, ModInt& rhs) noexcept {long long a; is >> a; rhs = a; return is;}
};

using mint = ModInt<MOD>;


struct ModCombination {
    vector<mint> Fac;
    vector<mint> Facinv;

    ModCombination(int x) {
        Fac.resize(x+1);
        Facinv.resize(x+1);
        Fac[0] = 1;
        for (int i = 0; i < x; ++i) Fac[i+1] = Fac[i]*(i+1);
        Facinv[x] = Fac[0]/Fac[x];
        for (int i = x; i > 0; --i) Facinv[i-1] = Facinv[i]*i;
    }

    mint get(int n, int k) {
        if (k < 0 || k > n) return 0;
        return Fac[n]*Facinv[k]*Facinv[n-k];
    }
};

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    ll N,M,A,B; cin >> N >> M >> A >> B;
    ModCombination MC(500000);

    ll t = B-A*(N-1);
    if (t < 0) {
        cout << 0 << ln;
        return 0;
    }
    mint ans = 0;
    for (ll i = 0; i <= t; i++) {
        ans += MC.get(N-2+i,i)*max(0LL,M-(A*(N-1)+i));
    }

    ans *= MC.Fac[N];
    cout << ans << ln;
}
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