#1010244 (C++23) No.2891 Mint

• 問題: No.2891 Mint
• ユーザー: k1suxu
• 提出日時: 2024-09-13 22:42:16
• 言語: C++23 (gcc 13.3.0 + boost 1.87.0)
• 結果: WA
• 実行時間: -
• コード長: 7,379 bytes
• コンパイル時間: 4,308 ms
• コンパイル使用メモリ: 268,632 KB
• 実行使用メモリ: 52,584 KB
• 最終ジャッジ日時: 2024-09-13 22:42:41
• 合計ジャッジ時間: 9,063 ms
• ジャッジサーバーID （参考情報）: judge1 / judge2

ファイルパターン	結果
sample	AC * 3
other	AC * 33 WA * 21

ソースコード

#pragma GCC target("avx")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
using namespace std;

#define rep(i,n) for(int i = 0; i < (int)n; i++)
#define FOR(n) for(int i = 0; i < (int)n; i++)
#define repi(i,a,b) for(int i = (int)a; i < (int)b; i++)
#define all(x) x.begin(),x.end()
//#define mp make_pair
#define vi vector<int>
#define vvi vector<vi>
#define vvvi vector<vvi>
#define vvvvi vector<vvvi>
#define pii pair<int,int>
#define vpii vector<pair<int,int>>

template<typename T>
bool chmax(T &a, const T b) {if(a<b) {a=b; return true;} else {return false;}}
template<typename T>
bool chmin(T &a, const T b) {if(a>b) {a=b; return true;} else {return false;}}

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

const ll INF = numeric_limits<long long>::max() / 2;
const ld pi = 3.1415926535897932384626433832795028;
const ll mod = 998244353;
int dx[] = {1, 0, -1, 0, -1, -1, 1, 1};
int dy[] = {0, 1, 0, -1, -1, 1, -1, 1};

#define int long long

template<long long MOD>
struct Modular_Int {
    using Mint_Type = Modular_Int<MOD>;
    long long x;

    Modular_Int() = default;
    Modular_Int(long long x_) : x(x_ >= 0? x_%MOD : (MOD-(-x_)%MOD)%MOD) {}

    long long val() const {
        return (x%MOD+MOD)%MOD;
    }
    static long long get_mod() {
        return MOD;
    }

    Mint_Type& operator^=(long long d)  {
        Mint_Type ret(1);
        long long nx = x;
        while(d) {
            if(d&1) ret *= nx;
            (nx *= nx) %= MOD;
            d >>= 1;
        }
        *this = ret;
        return *this;
    }
    Mint_Type operator^(long long d) const {return Mint_Type(*this) ^= d;}
    Mint_Type pow(long long d) const {return Mint_Type(*this) ^= d;}
    
    //use this basically
    Mint_Type inv() const {
        return Mint_Type(*this) ^ (MOD-2);
    }
    //only if the module number is not prime
    //Don't use. This is broken.
    // Mint_Type inv() const {
    //     long long a = (x%MOD+MOD)%MOD, b = MOD, u = 1, v = 0;
    //     while(b) {
    //         long long t = a/b;
    //         a -= t*b, swap(a, b);
    //         u -= t*v, swap(u, v);
    //     }
    //     return Mint_Type(u);
    // }

    Mint_Type& operator+=(const Mint_Type other) {
        if((x += other.x) >= MOD) x -= MOD;
        return *this;
    }
    Mint_Type& operator-=(const Mint_Type other) {
        if((x -= other.x) < 0) x += MOD;
        return *this;
    }
    Mint_Type& operator*=(const Mint_Type other) {
        long long z = x;
        z *= other.x;
        z %= MOD;
        x = z;
        if(x < 0) x += MOD;
        return *this;
    }
    Mint_Type& operator/=(const Mint_Type other) {
        return *this = *this * other.inv();
    }
    Mint_Type& operator++() {
        x++;
        if (x == MOD) x = 0;
        return *this;
    }
    Mint_Type& operator--() {
        if (x == 0) x = MOD;
        x--;
        return *this;
    }
    
    Mint_Type operator+(const Mint_Type other) const {return Mint_Type(*this) += other;}
    Mint_Type operator-(const Mint_Type other) const {return Mint_Type(*this) -= other;}
    Mint_Type operator*(const Mint_Type other) const {return Mint_Type(*this) *= other;}
    Mint_Type operator/(const Mint_Type other) const {return Mint_Type(*this) /= other;}
    
    Mint_Type& operator+=(const long long other) {Mint_Type other_(other); *this += other_; return *this;}
    Mint_Type& operator-=(const long long other) {Mint_Type other_(other); *this -= other_; return *this;}
    Mint_Type& operator*=(const long long other) {Mint_Type other_(other); *this *= other_; return *this;}
    Mint_Type& operator/=(const long long other) {Mint_Type other_(other); *this /= other_; return *this;}
    Mint_Type operator+(const long long other) const {return Mint_Type(*this) += other;}
    Mint_Type operator-(const long long other) const {return Mint_Type(*this) -= other;}
    Mint_Type operator*(const long long other) const {return Mint_Type(*this) *= other;}
    Mint_Type operator/(const long long other) const {return Mint_Type(*this) /= other;}

    bool operator==(const Mint_Type other) const {return (*this).val() == other.val();}
    bool operator!=(const Mint_Type other) const {return (*this).val() != other.val();}
    bool operator==(const long long other) const {return (*this).val() == other;}
    bool operator!=(const long long other) const {return (*this).val() != other;}

    Mint_Type operator-() const {return Mint_Type(0LL)-Mint_Type(*this);}

    //-1: sqrtが存在しない
    //複数存在する場合どれを返すかは不明
    long long get_sqrt() const {
        long long a = val(), p = get_mod();
        if(a == 0) return 0;
        if(p == 2) return a;
        if(Mint_Type(a).pow((p - 1) >> 1).val() != 1) return -1;
        long long b = 1;
        while(Mint_Type(b).pow((p - 1) >> 1).val() == 1) ++b;
        long long e = 0, m = p - 1;
        while(m % 2 == 0) m >>= 1, ++e;
        long long x = Mint_Type(a).pow((m - 1) >> 1).val();
        long long y = a * (x * x % p) % p;
        (x *= a) %= p;
        long long z = Mint_Type(b).pow(m).val();
        while(y != 1) {
            long long j = 0, t = y;
            while(t != 1) {
                j += 1;
                (t *= t) %= p;
            }
            z = Mint_Type(z).pow((long long)1 << (e - j - 1)).val();
            (x *= z) %= p;
            (z *= z) %= p;
            (y *= z) %= p;
            e = j;
        }
        return x;
    }

    template <typename T>
    friend Mint_Type operator+(T t, const Mint_Type& o) {
        return o + t;
    }
    template <typename T>
    friend Mint_Type operator-(T t, const Mint_Type& o) {
        return -o + t;
    }
    template <typename T>
    friend Mint_Type operator*(T t, const Mint_Type& o) {
        return o * t;
    }
    template <typename T>
    friend Mint_Type operator/(T t, const Mint_Type& o) {
        return o.inv() * t;
    }
};

// TODO: SELECT MOD_VAL
// const long long MOD_VAL = 1e9+7;
const long long MOD_VAL = 998244353;
using mint = Modular_Int<MOD_VAL>;

istream& operator>>(istream& is, mint& x) {
    long long X;
    is >> X;
    x = X;
    return is;
}
ostream& operator<<(ostream& os, mint& x) {
    os << x.val();
    return os;
}


// 1e9 + 7をmodとして使いたいときに注意！！！！特にCFやCCなどのAtCoder以外

//first: floor(N/[l,r]), second: [l,r](閉区間)
vector<pair<long long, pair<long long, long long>>> floor_quotient_ranges(long long N){
	vector<pair<long long, pair<long long, long long>>> ans;
	for (long long i = 1; i * i <= N; i++){
		ans.push_back(make_pair(N / i, make_pair(i, i)));
	}
	for (long long i = N / ((long long) sqrt(N) + 1); i >= 1; i--){
		ans.push_back(make_pair(i, make_pair(N / (i + 1) + 1, N / i)));
	}
	return ans;
}

mint range_sum(int l, int r) {
    return mint(l) * (r-l+1) +  (r-l) * (r-l+1) / 2;
}

void solve() {
    int n, m;
    cin >> n >> m;
    vector<pair<int, pii>> qrange = floor_quotient_ranges(m);
    mint ans = 0;
    for(auto e : qrange) if(e.second.first <= n) ans += m * (min(n, e.second.second) - e.second.first + 1) - e.first * range_sum(e.second.first, min(n, e.second.second));
    ans += m * max(0LL, n-m);
    cout << ans.val() << endl;
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    solve();
    return 0;
}