結果

問題 No.3118 Increment or Multiply
ユーザー rui_er
提出日時 2025-04-20 17:42:08
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 16 ms / 2,000 ms
コード長 3,294 bytes
コンパイル時間 2,126 ms
コンパイル使用メモリ 195,404 KB
実行使用メモリ 7,844 KB
最終ジャッジ日時 2025-04-20 17:42:12
合計ジャッジ時間 3,855 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge5
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 * 1
other AC * 35
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 # 

// Problem: No.3118 Increment or Multiply
// Contest: yukicoder
// URL: https://yukicoder.me/problems/no/3118
// Memory Limit: 512 MB
// Time Limit: 2000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

//By: OIer rui_er
#include <bits/stdc++.h>
#define rep(x, y, z) for(int x = (y); x <= (z); ++x)
#define per(x, y, z) for(int x = (y); x >= (z); --x)
#define debug(format...) fprintf(stderr, format)
#define fileIO(s) do {freopen(s".in", "r", stdin); freopen(s".out", "w", stdout);} while(false)
#define endl '\n'
using namespace std;
typedef long long ll;

mt19937 rnd(std::chrono::duration_cast<std::chrono::nanoseconds>(std::chrono::system_clock::now().time_since_epoch()).count());
int randint(int L, int R) {
    uniform_int_distribution<int> dist(L, R);
    return dist(rnd);
}

template<typename T> void chkmin(T& x, T y) {if(y < x) x = y;}
template<typename T> void chkmax(T& x, T y) {if(x < y) x = y;}

template<int mod>
inline unsigned int down(unsigned int x) {
	return x >= mod ? x - mod : x;
}

template<int mod>
struct Modint {
	unsigned int x;
	Modint() = default;
	Modint(unsigned int x) : x(x) {}
	friend istream& operator>>(istream& in, Modint& a) {return in >> a.x;}
	friend ostream& operator<<(ostream& out, Modint a) {return out << a.x;}
	friend Modint operator+(Modint a, Modint b) {return down<mod>(a.x + b.x);}
	friend Modint operator-(Modint a, Modint b) {return down<mod>(a.x - b.x + mod);}
	friend Modint operator*(Modint a, Modint b) {return 1ULL * a.x * b.x % mod;}
	friend Modint operator/(Modint a, Modint b) {return a * ~b;}
	friend Modint operator^(Modint a, int b) {Modint ans = 1; for(; b; b >>= 1, a *= a) if(b & 1) ans *= a; return ans;}
	friend Modint operator~(Modint a) {return a ^ (mod - 2);}
	friend Modint operator-(Modint a) {return down<mod>(mod - a.x);}
	friend Modint& operator+=(Modint& a, Modint b) {return a = a + b;}
	friend Modint& operator-=(Modint& a, Modint b) {return a = a - b;}
	friend Modint& operator*=(Modint& a, Modint b) {return a = a * b;}
	friend Modint& operator/=(Modint& a, Modint b) {return a = a / b;}
	friend Modint& operator^=(Modint& a, int b) {return a = a ^ b;}
	friend Modint& operator++(Modint& a) {return a += 1;}
	friend Modint operator++(Modint& a, int) {Modint x = a; a += 1; return x;}
	friend Modint& operator--(Modint& a) {return a -= 1;}
	friend Modint operator--(Modint& a, int) {Modint x = a; a -= 1; return x;}
	friend bool operator==(Modint a, Modint b) {return a.x == b.x;}
	friend bool operator!=(Modint a, Modint b) {return !(a == b);}
};

const int mod = 998244353;
typedef Modint<mod> mint;

ll T, n, a;

inline mint S(ll l, ll r) {return l > r ? 0 : (__int128)(l + r) * (r - l + 1) / 2 % mod;}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    for(cin >> T; T; --T) {
        cin >> n >> a;
        if(a == 1) {
            cout << S(0, n - 1) << endl;
        }
        else {
            mint ans = 0;
            ll now = 0;
            ans += S(0, n - n / a * a - 1);
            now = n - n / a * a;
            for(ll x = n / a * a; x; x = x / a) {
                ll l = x / a + 1, r = x;
                ans += S(now, now + (r - l));
                now += x - x / a * a + 1;
            }
            cout << ans << endl;
        }
    }
    return 0;
}
0