結果

問題 No.554 recurrence formula
ユーザー はまやんはまやん
提出日時 2017-08-13 08:48:20
言語 C++14
(gcc 7.2.0)
結果
AC  
実行時間 4 ms
コード長 3005 Byte
コンパイル時間 2102 ms
使用メモリ 1900 KB

テストケース

テストケース表示
入力 結果 実行時間
使用メモリ
test01.txt AC 4 ms
1880 KB
test02.txt AC 4 ms
1880 KB
test03.txt AC 4 ms
1884 KB
test04.txt AC 3 ms
1900 KB
test05.txt AC 4 ms
1896 KB
test06.txt AC 4 ms
1896 KB
test07.txt AC 3 ms
1896 KB
test08.txt AC 4 ms
1896 KB
test09.txt AC 4 ms
1900 KB
test10.txt AC 4 ms
1900 KB
test11.txt AC 4 ms
1896 KB
test12.txt AC 3 ms
1896 KB
test13.txt AC 4 ms
1900 KB
test14.txt AC 3 ms
1896 KB
test15.txt AC 4 ms
1900 KB
test16.txt AC 3 ms
1900 KB
test17.txt AC 4 ms
1892 KB
test18.txt AC 4 ms
1896 KB
test19.txt AC 4 ms
1900 KB
test20.txt AC 4 ms
1900 KB
test30.txt AC 4 ms
1900 KB
テストケース一括ダウンロード

ソースコード

diff #
#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=a;i>=b;i--)
#define fore(i,a) for(auto &i:a)
#pragma GCC optimize ("-O3")
using namespace std; void _main(); int main() { cin.tie(0); ios::sync_with_stdio(false); _main(); }
//---------------------------------------------------------------------------------------------------
template<int MOD> struct ModInt {
    static const int Mod = MOD; unsigned x; ModInt() : x(0) { }
    ModInt(signed sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    ModInt(signed long long sig) { x = sig < 0 ? sig % MOD + MOD : sig % MOD; }
    int get() const { return (int)x; }
    ModInt &operator+=(ModInt that) { if ((x += that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator-=(ModInt that) { if ((x += MOD - that.x) >= MOD) x -= MOD; return *this; }
    ModInt &operator*=(ModInt that) { x = (unsigned long long)x * that.x % MOD; return *this; }
    ModInt &operator/=(ModInt that) { return *this *= that.inverse(); }
    ModInt operator+(ModInt that) const { return ModInt(*this) += that; }
    ModInt operator-(ModInt that) const { return ModInt(*this) -= that; }
    ModInt operator*(ModInt that) const { return ModInt(*this) *= that; }
    ModInt operator/(ModInt that) const { return ModInt(*this) /= that; }
    ModInt inverse() const { long long a = x, b = MOD, u = 1, v = 0;
        while (b) { long long t = a / b; a -= t * b; std::swap(a, b); u -= t * v; std::swap(u, v); }
        return ModInt(u); }
    bool operator==(ModInt that) const { return x == that.x; }
    bool operator!=(ModInt that) const { return x != that.x; }
    ModInt operator-() const { ModInt t; t.x = x == 0 ? 0 : Mod - x; return t; }
};
template<int MOD> ostream& operator<<(ostream& st, const ModInt<MOD> a) { st << a.get(); return st; };
template<int MOD> ModInt<MOD> operator^(ModInt<MOD> a, unsigned long long k) {
    ModInt<MOD> r = 1; while (k) { if (k & 1) r *= a; a *= a; k >>= 1; } return r; }
typedef ModInt<1000000007> mint;
/*---------------------------------------------------------------------------------------------------
            ∧_∧  
      ∧_∧  (´<_` )  Welcome to My Coding Space!
     ( ´_ゝ`) /  ⌒i     
    /   \     | |     
    /   / ̄ ̄ ̄ ̄/  |  
  __(__ニつ/     _/ .| .|____  
     \/____/ (u ⊃  
---------------------------------------------------------------------------------------------------*/



int N;
mint A[101010];
//---------------------------------------------------------------------------------------------------
void _main() {
    cin >> N;

    mint odd = 0, even = 0;
    A[1] = 1;
    odd = A[1];

    rep(i, 2, N + 1) {
        if (i % 2 == 0) {
            A[i] = odd * i;
            even += A[i];
        } else {
            A[i] = even * i;
            odd += A[i];
        }
    }

    cout << A[N] << endl;
}
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