#446816 (C++17) No.1011 Infinite Stairs

• 問題: No.1011 Infinite Stairs
• ユーザー: chocopuu
• 提出日時: 2020-03-20 22:03:31
• 言語: C++17 (gcc 12.3.0 + boost 1.83.0)
• 結果: AC
• 実行時間: 131 ms / 2,000 ms
• コード長: 3,443 bytes
• コンパイル時間: 2,084 ms
• コンパイル使用メモリ: 205,876 KB
• 実行使用メモリ: 6,944 KB
• 最終ジャッジ日時: 2024-07-17 11:50:03
• 合計ジャッジ時間: 3,450 ms
• ジャッジサーバーID （参考情報）: judge3 / judge1

入力	結果	実行時間; 実行使用メモリ
testcase_00	AC	2 ms; 6,812 KB
testcase_01	AC	2 ms; 6,944 KB
testcase_02	AC	3 ms; 6,940 KB
testcase_03	AC	85 ms; 6,944 KB
testcase_04	AC	16 ms; 6,940 KB
testcase_05	AC	131 ms; 6,940 KB
testcase_06	AC	2 ms; 6,944 KB
testcase_07	AC	3 ms; 6,940 KB
testcase_08	AC	2 ms; 6,940 KB
testcase_09	AC	2 ms; 6,940 KB
testcase_10	AC	3 ms; 6,944 KB
testcase_11	AC	19 ms; 6,940 KB
testcase_12	AC	3 ms; 6,940 KB
testcase_13	AC	12 ms; 6,940 KB
testcase_14	AC	2 ms; 6,940 KB
testcase_15	AC	15 ms; 6,940 KB
testcase_16	AC	59 ms; 6,944 KB
testcase_17	AC	7 ms; 6,944 KB
testcase_18	AC	35 ms; 6,940 KB
testcase_19	AC	2 ms; 6,940 KB
testcase_20	AC	2 ms; 6,944 KB
testcase_21	AC	16 ms; 6,940 KB
testcase_22	AC	29 ms; 6,940 KB
testcase_23	AC	18 ms; 6,944 KB
testcase_24	AC	19 ms; 6,940 KB
testcase_25	AC	30 ms; 6,940 KB
testcase_26	AC	8 ms; 6,940 KB

ソースコード

#include "bits/stdc++.h"
using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (int)(n); ++i)
#define RREP(i, n) for (int i = (int)n - 1; i >= 0; --i)
#define FOR(i, s, n) for (int i = s; i < (int)n; ++i)
#define RFOR(i, s, n) for (int i = (int)n - 1; i >= s; --i)
#define ALL(a) a.begin(), a.end()
#define IN(a, x, b) (a <= x && x < b)
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a = b;return true;}return false;}
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a = b;return true;}return false;}

template<int MOD> struct Fp {
	long long val;
	constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
		if (val < 0) val += MOD;
	}
	constexpr int getmod() { return MOD; }
	constexpr Fp operator - () const noexcept {
		return val ? MOD - val : 0;
	}
	constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
	constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
	constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
	constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
	constexpr Fp& operator += (const Fp& r) noexcept {
		val += r.val;
		if (val >= MOD) val -= MOD;
		return *this;
	}
	constexpr Fp& operator -= (const Fp& r) noexcept {
		val -= r.val;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr Fp& operator *= (const Fp& r) noexcept {
		val = val * r.val % MOD;
		return *this;
	}
	constexpr Fp& operator /= (const Fp& r) noexcept {
		long long a = r.val, b = MOD, u = 1, v = 0;
		while (b) {
			long long t = a / b;
			a -= t * b; swap(a, b);
			u -= t * v; swap(u, v);
		}
		val = val * u % MOD;
		if (val < 0) val += MOD;
		return *this;
	}
	constexpr bool operator == (const Fp& r) const noexcept {
		return this->val == r.val;
	}
	constexpr bool operator != (const Fp& r) const noexcept {
		return this->val != r.val;
	}
	friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept {
		return os << x.val;
	}
	friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
		if (n == 0) return 1;
		auto t = modpow(a, n / 2);
		t = t * t;
		if (n & 1) t = t * a;
		return t;
	}
};
 
// 二項係数ライブラリ
template<class T> struct BiCoef {
	vector<T> fact_, inv_, finv_;
	constexpr BiCoef() {}
	constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
		init(n);
	}
	constexpr void init(int n) noexcept {
		fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
		int MOD = fact_[0].getmod();
		for(int i = 2; i < n; i++){
			fact_[i] = fact_[i-1] * i;
			inv_[i] = -inv_[MOD%i] * (MOD/i);
			finv_[i] = finv_[i-1] * inv_[i];
		}
	}
	constexpr T com(int n, int k) const noexcept {
		if (n < k || n < 0 || k < 0) return 0;
		return fact_[n] * finv_[k] * finv_[n-k];
	}
	constexpr T fact(int n) const noexcept {
		if (n < 0) return 0;
		return fact_[n];
	}
	constexpr T inv(int n) const noexcept {
		if (n < 0) return 0;
		return inv_[n];
	}
	constexpr T finv(int n) const noexcept {
		if (n < 0) return 0;
		return finv_[n];
	}
};
 
const int MOD = 1000000007;
// const int MOD = 
using mint = Fp<MOD>;
BiCoef<mint> bc;
// bc.init(500050);

signed main(){
	int N,D,K;
	cin >> N >> D >> K;
	vector<mint>dp(K + 1);
	dp[0] = 1;
	REP(i,N){
		vector<mint>ndp(K + 1);
		REP(j,K){
			ndp[j + 1] += dp[j];
			if(j + 1 + D <= K)ndp[j + 1 + D] -= dp[j];
		}
		REP(j,K)ndp[j + 1] += ndp[j];
		dp = ndp;
	}
	cout << dp[K] << endl;
}