結果
問題 | No.2384 Permutations of Permutations |
ユーザー |
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提出日時 | 2023-07-14 23:19:05 |
言語 | C++17 (gcc 13.3.0 + boost 1.87.0) |
結果 |
WA
|
実行時間 | - |
コード長 | 3,003 bytes |
コンパイル時間 | 3,867 ms |
コンパイル使用メモリ | 264,556 KB |
最終ジャッジ日時 | 2025-02-15 14:45:26 |
ジャッジサーバーID (参考情報) |
judge2 / judge3 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 1 WA * 1 |
other | AC * 1 WA * 21 |
ソースコード
#include<bits/stdc++.h> #include<atcoder/all> using namespace std; using namespace atcoder; typedef modint998244353 mint; typedef long long ll; #define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++) #define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--) template <typename T> bool chmin(T &a, const T &b) { if (a <= b) return false; a = b; return true; } template <typename T> bool chmax(T &a, const T &b) { if (a >= b) return false; a = b; return true; } //defmodfact const int COMinitMAX = 998244; mint fact[COMinitMAX+1], factinv[COMinitMAX+1]; void modfact(){ fact[0] = 1; for (int i=1; i<=COMinitMAX; i++){ fact[i] = fact[i-1] * i; } factinv[COMinitMAX] = fact[COMinitMAX].inv(); for (int i=COMinitMAX-1; i>=0; i--){ factinv[i] = factinv[i+1] * (i+1); } } mint cmb(int a, int b){ if (a<b || b<0) return mint(0); return fact[a]*factinv[b]*factinv[a-b]; } //-------- vector<mint> poly_inv(vector<mint> &a, int M = -314159265){ if (M == -314159265) M = (int)a.size(); else if (M <= 0) return {}; int n = a.size(); mint r = a[0].pow((ll)(mint::mod())-2); int m = 1; vector<mint> res = {r}; while (m < M){ vector<mint> f = a; f.resize(2 * m); vector<mint> g = res; g.resize(2 * m); internal::butterfly(f); internal::butterfly(g); for (int i=0; i<2*m; i++){ f[i] = f[i] * g[i]; } internal::butterfly_inv(f); for (int i=0; i<m; i++){ f[i] = f[i + m]; } for (int i=0; i<m; i++){ f[i + m] = 0; } internal::butterfly(f); for (int i=0; i<2*m; i++){ f[i] = f[i] * g[i]; } internal::butterfly_inv(f); mint iz = mint(2*m).inv(); iz = -iz * iz; for (int i=0; i<m; i++){ f[i] = f[i] * iz; } res.insert(res.end(), f.begin(), f.begin()+m); m <<= 1; } res.resize(M); return res; } vector<mint> poly_log(vector<mint> &a, int M = -314159265){ if (M == -314159265) M = (int)a.size(); else if (M <= 0) return {}; int n = a.size(); if (n == 1) return vector<mint>(M, 0); vector<mint> b(n-1); for (int i=0; i<n-1; i++){ b[i] = a[i+1] * (i+1); } vector<mint> t = convolution<mint>(b, poly_inv(a, M)); vector<mint> ret(M); for (int i=0; i<M-1; i++){ ret[i+1] = t[i] * factinv[i+1] * fact[i]; } return ret; } vector<mint> poly_exp(vector<mint> &a, int M = -314159265){ if (M == -314159265) M = (int)a.size(); else if (M <= 0) return {}; int n = a.size(); int m = 1; vector<mint> res = {1}; while (m < M){ vector<mint> f(2*m); for (int i=0; i<min(n, 2*m); i++) f[i] = a[i]; vector<mint> v = poly_log(res, 2*m); vector<mint> w(2*m); for (int i=0; i<2*m; i++) w[i] = f[i] - v[i]; w[0] += 1; vector<mint> g = convolution<mint>(res, w); res.insert(res.end(), g.begin()+m, g.begin()+2*m); m <<= 1; } res.resize(M); return res; } int main(){ modfact(); int n, k; cin >> n >> k; vector<mint> g(n+1); rep(i,1,n+1){ if (k%i == 0){ g[i] = mint(i).inv(); } } vector<mint> f = poly_exp(g); mint ans = f[n] * fact[n] * factinv[k]; cout << ans.val() << endl; }