結果

問題 No.3095 Many Min Problems
ユーザー Today03
提出日時 2025-04-07 02:18:11
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 133 ms / 2,000 ms
コード長 3,241 bytes
コンパイル時間 3,038 ms
コンパイル使用メモリ 275,864 KB
実行使用メモリ 7,844 KB
最終ジャッジ日時 2025-04-07 02:18:18
合計ジャッジ時間 6,100 ms
ジャッジサーバーID
(参考情報)
judge5 / judge3
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ファイルパターン 結果
sample AC * 3
other AC * 30
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>
#define ALL(x) (x).begin(), (x).end()
#define LB(v, x) (int)(lower_bound(ALL(v), x) - (v).begin())
#define UQ(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define IO ios::sync_with_stdio(false), cin.tie(nullptr);
#define chmax(a, b) (a) = (a) < (b) ? (b) : (a)
#define chmin(a, b) (a) = (a) < (b) ? (a) : (b)
using namespace std;
using ll = long long;
const int INF = 1e9 + 10;
const ll INFL = 4e18;

/// @file modint.hpp
/// @brief ModInt
template <ll MOD>
struct ModInt {
    ModInt(ll x = 0) { value = (x >= 0 ? x % MOD : 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;
    }
    ll val() { return value; }
    static constexpr ll get_mod() { return MOD; }

private:
    ll value;
};
using Mod998 = ModInt<998244353>;
using Mod107 = ModInt<1000000007>;

using mint = Mod998;

int main() {
    ll N, M;
    cin >> N >> M;

    mint p1 = 0;
    {
        for (int j = 1; j <= M; j++) {
            mint add = j;
            int start = M - j + 1;
            mint r = mint(M - j + 1) / M;
            if (r.val() == 1) {
                add *= (mint)start * N;
            } else {
                add *= mint(start) * (r.pow(N) - 1) / (r - 1);
            }
            p1 += add;
        }
    }
    mint p2 = 0;
    {
        for (int j = 1; j < M; j++) {
            mint add = j;
            int start = M - j;
            mint r = mint(M - j) / M;
            if (r.val() == 1) {
                add *= (mint)start * N;
            } else {
                add *= mint(start) * (mint(r).pow(N) - 1) / (r - 1);
            }
            p2 += add;
        }
    }

    mint ans = p1 - p2;
    ans *= mint(M).pow(N - 1);
    cout << ans << endl;
}
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