結果

問題 No.523 LED
ユーザー oshibori
提出日時 2017-06-02 23:00:27
言語 C++11（廃止可能性あり）
(gcc 13.3.0)
結果
AC  
実行時間 167 ms / 2,000 ms
コード長 3,240 bytes
コンパイル時間 1,429 ms
コンパイル使用メモリ 162,468 KB
実行使用メモリ 81,280 KB
最終ジャッジ日時 2024-09-22 02:45:34
合計ジャッジ時間 3,368 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge3
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ファイルパターン 結果
other AC * 25
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ソースコード

diff # 

#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; }
//by anta

//20160723
//http://arc058.contest.atcoder.jp/submissions/815261

template<int MOD>
struct ModInt {
	static const int Mod = MOD;
	unsigned x;
	ModInt() : x(0) {}
	ModInt(signed sig) { int sigt = sig % MOD; if (sigt < 0) sigt += MOD; x = sigt; }
	ModInt(signed long long sig) { int sigt = sig % MOD; if (sigt < 0) sigt += MOD; x = sigt; }
	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 {
		signed a = x, b = MOD, u = 1, v = 0;
		while (b) {
			signed t = a / b;
			a -= t * b; std::swap(a, b);
			u -= t * v; std::swap(u, v);
		}
		if (u < 0) u += MOD;
		ModInt res; res.x = (unsigned)u;
		return res;
	}
};
template <int M>
ostream &operator << (ostream &os, const ModInt<M> &m) { return os << m.x; }
template <int M>
istream &operator >> (istream &is, ModInt<M> &m) { signed long long s; is >> s; m = ModInt<M>(s); return is; };
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;
}

using mint = ModInt<1000000007>;

//nCrで用いる
vector<mint> fact, factinv;
//nCrで用いる 予め計算しておく
void nCr_compute_factinv(int N) {
	N = min(N, mint::Mod - 1);
	fact.resize(N + 1); factinv.resize(N + 1);
	fact[0] = 1;
	rep(i, 1, N + 1) fact[i] = fact[i - 1] * i;
	factinv[N] = fact[N].inverse();
	for (int i = N; i >= 1; i--) factinv[i - 1] = factinv[i] * i;
}
mint nCr(int n, int r) {
	if (n >= mint::Mod)
		return nCr(n % mint::Mod, r % mint::Mod) * nCr(n / mint::Mod, r / mint::Mod);
	return r > n ? 0 : fact[n] * factinv[n - r] * factinv[r];
}

int mod_pow(int x, int n) {
	int res(1);
	while (n > 0) {
		if (n & 1)res = res*x%MOD;
		x = x*x%MOD;
		n >>= 1;
	}

	return res;
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N; cin >> N;
	vector<ModInt<MOD>>f(2 * N + 1);
	f[0] = 1;
	rep(i, 1, f.size())f[i] = (f[i - 1] * i);
	ModInt<MOD> ans(f[2 * N]);
	ans /= mod_pow(2, N);
	cout << ans << endl;

	return 0;
}
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