結果

問題 No.665 Bernoulli Bernoulli
ユーザー 👑 emthrmemthrm
提出日時 2020-03-03 22:16:31
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 7 ms / 2,000 ms
コード長 4,664 bytes
コンパイル時間 2,487 ms
コンパイル使用メモリ 198,180 KB
実行使用メモリ 5,376 KB
最終ジャッジ日時 2024-04-22 00:39:04
合計ジャッジ時間 3,107 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
5,248 KB
testcase_01 AC 2 ms
5,376 KB
testcase_02 AC 4 ms
5,376 KB
testcase_03 AC 7 ms
5,376 KB
testcase_04 AC 7 ms
5,376 KB
testcase_05 AC 7 ms
5,376 KB
testcase_06 AC 6 ms
5,376 KB
testcase_07 AC 7 ms
5,376 KB
testcase_08 AC 7 ms
5,376 KB
testcase_09 AC 7 ms
5,376 KB
testcase_10 AC 7 ms
5,376 KB
testcase_11 AC 7 ms
5,376 KB
testcase_12 AC 6 ms
5,376 KB
testcase_13 AC 7 ms
5,376 KB
testcase_14 AC 7 ms
5,376 KB
testcase_15 AC 6 ms
5,376 KB
testcase_16 AC 6 ms
5,376 KB
testcase_17 AC 7 ms
5,376 KB
testcase_18 AC 7 ms
5,376 KB
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 # 

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) (v).begin(),(v).end()
using ll = long long;
const int INF = 0x3f3f3f3f;
const ll LINF = 0x3f3f3f3f3f3f3f3fLL;
const double EPS = 1e-8;
const int MOD = 1000000007;
// const int MOD = 998244353;
const int dy[] = {1, 0, -1, 0}, dx[] = {0, -1, 0, 1};
const int dy8[] = {1, 1, 0, -1, -1, -1, 0, 1}, dx8[] = {0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U> inline bool chmax(T &a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U> inline bool chmin(T &a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(20);
  }
} iosetup;

int mod = MOD;
struct ModInt {
  unsigned val;
  ModInt(): val(0) {}
  ModInt(ll x) : val(x >= 0 ? x % mod : x % mod + mod) {}
  ModInt pow(ll exponent) {
    ModInt tmp = *this, res = 1;
    while (exponent > 0) {
      if (exponent & 1) res *= tmp;
      tmp *= tmp;
      exponent >>= 1;
    }
    return res;
  }
  ModInt &operator+=(const ModInt &x) { if((val += x.val) >= mod) val -= mod; return *this; }
  ModInt &operator-=(const ModInt &x) { if((val += mod - x.val) >= mod) val -= mod; return *this; }
  ModInt &operator*=(const ModInt &x) { val = static_cast<unsigned long long>(val) * x.val % mod; return *this; }
  ModInt &operator/=(const ModInt &x) {
    // assert(__gcd(static_cast<int>(x.val), mod) == 1);
    unsigned a = x.val, b = mod; int u = 1, v = 0;
    while (b) {
      unsigned tmp = a / b;
      swap(a -= tmp * b, b);
      swap(u -= tmp * v, v);
    }
    return *this *= u;
  }
  bool operator==(const ModInt &x) const { return val == x.val; }
  bool operator!=(const ModInt &x) const { return val != x.val; }
  bool operator<(const ModInt &x) const { return val < x.val; }
  bool operator<=(const ModInt &x) const { return val <= x.val; }
  bool operator>(const ModInt &x) const { return val > x.val; }
  bool operator>=(const ModInt &x) const { return val >= x.val; }
  ModInt &operator++() { if (++val == mod) val = 0; return *this; }
  ModInt operator++(int) { ModInt res = *this; ++*this; return res; }
  ModInt &operator--() { val = (val == 0 ? mod : val) - 1; return *this; }
  ModInt operator--(int) { ModInt res = *this; --*this; return res; }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { return ModInt(val ? mod - val : 0); }
  ModInt operator+(const ModInt &x) const { return ModInt(*this) += x; }
  ModInt operator-(const ModInt &x) const { return ModInt(*this) -= x; }
  ModInt operator*(const ModInt &x) const { return ModInt(*this) *= x; }
  ModInt operator/(const ModInt &x) const { return ModInt(*this) /= x; }
  friend ostream &operator<<(ostream &os, const ModInt &x) { return os << x.val; }
  friend istream &operator>>(istream &is, ModInt &x) { ll val; is >> val; x = ModInt(val); return is; }
};
ModInt abs(const ModInt &x) { return x; }
struct Combinatorics {
  int val; // "val!" and "mod" must be disjoint.
  vector<ModInt> fact, fact_inv, inv;
  Combinatorics(int val = 10000000) : val(val), fact(val + 1), fact_inv(val + 1), inv(val + 1) {
    fact[0] = 1;
    FOR(i, 1, val + 1) fact[i] = fact[i - 1] * i;
    fact_inv[val] = ModInt(1) / fact[val];
    for (int i = val; i > 0; --i) fact_inv[i - 1] = fact_inv[i] * i;
    FOR(i, 1, val + 1) inv[i] = fact[i - 1] * fact_inv[i];
  }
  ModInt nCk(int n, int k) {
    if (n < 0 || n < k || k < 0) return ModInt(0);
    // assert(n <= val && k <= val);
    return fact[n] * fact_inv[k] * fact_inv[n - k];
  }
  ModInt nPk(int n, int k) {
    if (n < 0 || n < k || k < 0) return ModInt(0);
    // assert(n <= val);
    return fact[n] * fact_inv[n - k];
  }
  ModInt nHk(int n, int k) {
    if (n < 0 || k < 0) return ModInt(0);
    return (k == 0 ? ModInt(1) : nCk(n + k - 1, k));
  }
};

template <typename T>
T lagrange_interpolation(const vector<T> &y, T t) {
  int n = y.size();
  assert(t < 0 || t >= n);
  vector<T> fact(n, 1);
  FOR(i, 1, n) fact[i] = fact[i - 1] * i;
  T res = 0;
  REP(i, n) {
    T den = (t - i) * fact[i] * fact[n - 1 - i];
    if ((n - 1 - i) & 1) den = -den;
    res += y[i] / den;
  }
  REP(i, n) res *= t - i;
  return res;
}

ModInt faulhaber(ll n, int k) {
  if (n < 1) return 0;
  vector<ModInt> y(k + 2, 0);
  FOR(i, 1, k + 2) y[i] = y[i - 1] + ModInt(i).pow(k);
  if (n - 1 < k + 2) return y[n - 1];
  return lagrange_interpolation(y, ModInt(n - 1));
}

int main() {
  ll n; int k; cin >> n >> k;
  cout << faulhaber(n + 1, k) << '\n';
  return 0;
}
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