結果

問題 No.2891 Mint
ユーザー ecottea
提出日時 2024-09-13 22:20:44
言語 C++17(gcc12)
(gcc 12.3.0 + boost 1.87.0)
結果
AC  
実行時間 65 ms / 2,000 ms
コード長 7,724 bytes
コンパイル時間 6,597 ms
コンパイル使用メモリ 301,100 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-09-13 22:20:53
合計ジャッジ時間 9,146 ms
ジャッジサーバーID
(参考情報)
judge5 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 54
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 #
プレゼンテーションモードにする

// QCFium
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#ifndef HIDDEN_IN_VS //
//
#define _CRT_SECURE_NO_WARNINGS
//
#include <bits/stdc++.h>
using namespace std;
//
using ll = long long; using ull = unsigned long long; // -2^63 2^63 = 9e18int -2^31 2^31 = 2e9
using pii = pair<int, int>; using pll = pair<ll, ll>; using pil = pair<int, ll>; using pli = pair<ll, int>;
using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>; using vvvvi = vector<vvvi>;
using vl = vector<ll>; using vvl = vector<vl>; using vvvl = vector<vvl>; using vvvvl = vector<vvvl>;
using vb = vector<bool>; using vvb = vector<vb>; using vvvb = vector<vvb>;
using vc = vector<char>; using vvc = vector<vc>; using vvvc = vector<vvc>;
using vd = vector<double>; using vvd = vector<vd>; using vvvd = vector<vvd>;
template <class T> using priority_queue_rev = priority_queue<T, vector<T>, greater<T>>;
using Graph = vvi;
//
const double PI = acos(-1);
int DX[4] = { 1, 0, -1, 0 }; // 4
int DY[4] = { 0, 1, 0, -1 };
int INF = 1001001001; ll INFL = 4004004003094073385LL; // (int)INFL = INF, (int)(-INFL) = -INF;
//
struct fast_io { fast_io() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(18); } } fastIOtmp;
//
#define all(a) (a).begin(), (a).end()
#define sz(x) ((int)(x).size())
#define lbpos(a, x) (int)distance((a).begin(), std::lower_bound(all(a), x))
#define ubpos(a, x) (int)distance((a).begin(), std::upper_bound(all(a), x))
#define Yes(b) {cout << ((b) ? "Yes\n" : "No\n");}
#define rep(i, n) for(int i = 0, i##_len = int(n); i < i##_len; ++i) // 0 n-1
#define repi(i, s, t) for(int i = int(s), i##_end = int(t); i <= i##_end; ++i) // s t
#define repir(i, s, t) for(int i = int(s), i##_end = int(t); i >= i##_end; --i) // s t
#define repe(v, a) for(const auto& v : (a)) // a
#define repea(v, a) for(auto& v : (a)) // a
#define repb(set, d) for(int set = 0, set##_ub = 1 << int(d); set < set##_ub; ++set) // d
#define repis(i, set) for(int i = lsb(set), bset##i = set; i < 32; bset##i -= 1 << i, i = lsb(bset##i)) // set
#define repp(a) sort(all(a)); for(bool a##_perm = true; a##_perm; a##_perm = next_permutation(all(a))) // a
#define uniq(a) {sort(all(a)); (a).erase(unique(all(a)), (a).end());} //
#define EXIT(a) {cout << (a) << endl; exit(0);} //
#define inQ(x, y, u, l, d, r) ((u) <= (x) && (l) <= (y) && (x) < (d) && (y) < (r)) //
//
template <class T> inline ll powi(T n, int k) { ll v = 1; rep(i, k) v *= n; return v; }
template <class T> inline bool chmax(T& M, const T& x) { if (M < x) { M = x; return true; } return false; } // true
    
template <class T> inline bool chmin(T& m, const T& x) { if (m > x) { m = x; return true; } return false; } // true
    
template <class T> inline T getb(T set, int i) { return (set >> i) & T(1); }
template <class T> inline T smod(T n, T m) { n %= m; if (n < 0) n += m; return n; } // mod
//
template <class T, class U> inline istream& operator>>(istream& is, pair<T, U>& p) { is >> p.first >> p.second; return is; }
template <class T> inline istream& operator>>(istream& is, vector<T>& v) { repea(x, v) is >> x; return is; }
template <class T> inline vector<T>& operator--(vector<T>& v) { repea(x, v) --x; return v; }
template <class T> inline vector<T>& operator++(vector<T>& v) { repea(x, v) ++x; return v; }
#endif //
#if __has_include(<atcoder/all>)
#include <atcoder/all>
using namespace atcoder;
#ifdef _MSC_VER
#include "localACL.hpp"
#endif
//using mint = modint1000000007;
using mint = modint998244353;
//using mint = static_modint<(ll)1e9>;
//using mint = modint; // mint::set_mod(m);
namespace atcoder {
inline istream& operator>>(istream& is, mint& x) { ll x_; is >> x_; x = x_; return is; }
inline ostream& operator<<(ostream& os, const mint& x) { os << x.val(); return os; }
}
using vm = vector<mint>; using vvm = vector<vm>; using vvvm = vector<vvm>; using vvvvm = vector<vvvm>; using pim = pair<int, mint>;
#endif
#ifdef _MSC_VER // Visual Studio
#include "local.hpp"
#else // gcc
inline int popcount(int n) { return __builtin_popcount(n); }
inline int popcount(ll n) { return __builtin_popcountll(n); }
inline int lsb(int n) { return n != 0 ? __builtin_ctz(n) : 32; }
inline int lsb(ll n) { return n != 0 ? __builtin_ctzll(n) : 64; }
template <size_t N> inline int lsb(const bitset<N>& b) { return b._Find_first(); }
inline int msb(int n) { return n != 0 ? (31 - __builtin_clz(n)) : -1; }
inline int msb(ll n) { return n != 0 ? (63 - __builtin_clzll(n)) : -1; }
#define dump(...)
#define dumpel(v)
#define dump_list(v)
#define dump_mat(v)
#define input_from_file(f)
#define output_to_file(f)
#define Assert(b) { if (!(b)) { vc MLE(1<<30); EXIT(MLE.back()); } } // RE MLE
#endif
//O(√n)
/*
* [1..n] n/i = q i∈(il..ir]
* i f(il, ir, q)
* n mod i -q
*/
template <class T, class FUNC>
void quotient_range(T n, const FUNC& f) {
// : https://ei1333.github.io/luzhiled/snippets/math/quotient-range.html
// verify : https://judge.yosupo.jp/problem/enumerate_quotients
//
// n/i q i i
// q = floor(n/i)
// ⇔ q ≦ n/i < q+1
// ⇔ i q ≦ n < i(q+1)
// ⇔ n/(q+1) < i ≦ n/q (⇔ floor(n/(q+1)) < i ≦ floor(n/q))
//
//
// 1 q i 1
// n/q - n/(q+1) ≦ 1
// ⇔ (q+1)n - q n ≦ q(q+1)
// ⇔ n ≦ q(q+1)
//
// n ≦ q^2 ⇔ √n ≦ q
//
//
// n = 15 (0..15]
// i q=n/i n mod i
// (0..1] 15 [0]
// (1..2] 7 [1]
// (2..3] 5 [0]
// (3..5] 3 [3, 0]
// (5..7] 2 [3, 1]
// (7..15] 1 [7, 6, 5, 4, 3, 2, 1, 0]
T sqrt_n = (T)(sqrt(n) - 1e-9);
// q i 1 i
T i_max = n / (sqrt_n + 1);
for (T i = 1; i <= i_max; ++i) f(i - 1, i, n / i);
// q
T il, ir = i_max;
for (T q = sqrt_n; q >= 1; --q) {
il = ir;
ir = n / q;
f(il, ir, q);
}
/* f
using T = ll;
auto f = [&](T il, T ir, T q) {
};
*/
}
int main() {
// input_from_file("input.txt");
// output_to_file("output.txt");
ll n, m;
cin >> n >> m;
mint res = 0; mint inv2 = mint(2).inv();
using T = ll;
auto f = [&](T il, T ir, T q) {
chmin(ir, n);
if (il > ir) return;
ll a = m % (il + 1);
ll b = m % ir;
res += inv2 * (a + b) * (ir - il);
};
quotient_range(m, f);
dump(res);
if (m < n) {
ll a = m % (m + 1);
ll b = m % n;
res += inv2 * (a + b) * (n - m);
}
EXIT(res);
}
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