#446959 (C++17) No.1011 Infinite Stairs

• 問題: No.1011 Infinite Stairs
• ユーザー: Haar
• 提出日時: 2020-03-20 22:24:13
• 言語: C++17 (gcc 13.3.0 + boost 1.87.0)
• 結果: AC
• 実行時間: 277 ms / 2,000 ms
• コード長: 6,255 bytes
• コンパイル時間: 2,671 ms
• コンパイル使用メモリ: 197,928 KB
• 最終ジャッジ日時: 2025-01-09 08:42:24
• ジャッジサーバーID （参考情報）: judge2 / judge1

ファイルパターン	結果
sample	AC * 3
other	AC * 24

ソースコード

#include <bits/stdc++.h>

using i32 = int_fast32_t;
using i64 = int_fast64_t;
using u32 = uint_fast32_t;
using u64 = uint_fast64_t;
using f64 = double;
using f80 = long double;

#define FOR(v, a, b) for(i64 v = (a); v < (b); ++v)
#define FORE(v, a, b) for(i64 v = (a); v <= (b); ++v)
#define REP(v, n) FOR(v, 0, n)
#define REPE(v, n) FORE(v, 0, n)
#define REV(v, a, b) for(i64 v = (a); v >= (b); --v)
#define ALL(x) (x).begin(), (x).end()
#define RALL(x) (x).rbegin(), (x).rend()
#define ITR(it, c) for(auto it = (c).begin(); it != (c).end(); ++it)
#define RITR(it, c) for(auto it = (c).rbegin(); it != (c).rend(); ++it)
#define EXIST(c,x) ((c).find(x) != (c).end())
#define fst first
#define snd second
#define UNIQ(v) (v).erase(unique(ALL(v)), (v).end())
#define bit(i) (1LL<<(i))

#ifdef DEBUG
#include <Mylib/Debug/debug.cpp>
#else
#define dump(...) ((void)0)
#endif

using namespace std;

template <typename I> void join(ostream &ost, I s, I t, string d=" "){for(auto i=s; i!=t; ++i){if(i!=s)ost<<d; ost<<*i;}ost<<endl;}
template <typename T> istream& operator>>(istream &is, vector<T> &v){for(auto &a : v) is >> a; return is;}
template <typename T> void puts_all(const T &value){std::cout << value << "\n";}
template <typename T, typename ...Args> void puts_all(const T &value, const Args&... args){std::cout << value << " ";puts_all(args...);}

template <typename T, typename U> bool chmin(T &a, const U &b){return (a>b ? a=b, true : false);}
template <typename T, typename U> bool chmax(T &a, const U &b){return (a<b ? a=b, true : false);}
template <typename T, size_t N, typename U> void fill_array(T (&a)[N], const U &v){fill((U*)a, (U*)(a+N), v);}
template <typename T> auto make_vector(int n, int m, const T &value){return vector<vector<T>>(n, vector<T>(m, value));}


struct Init{
  Init(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(12);
    cerr << fixed << setprecision(12);
  }
}init;


template <uint32_t M> class ModInt{
public:
  uint64_t val;
  
  constexpr ModInt(): val(0){}
  constexpr ModInt(std::int64_t n){
    if(n >= M) val = n % M;
    else if(n < 0) val = n % M + M;
    else val = n;
  }
  
  inline constexpr auto operator+(const ModInt &a) const {return ModInt(val + a.val);}
  inline constexpr auto operator-(const ModInt &a) const {return ModInt(val - a.val);}
  inline constexpr auto operator*(const ModInt &a) const {return ModInt(val * a.val);}
  inline constexpr auto operator/(const ModInt &a) const {return ModInt(val * a.inv().val);}
  
  inline constexpr auto& operator=(const ModInt &a){val = a.val; return *this;}
  inline constexpr auto& operator+=(const ModInt &a){if((val += a.val) >= M) val -= M; return *this;}
  inline constexpr auto& operator-=(const ModInt &a){if(val < a.val) val += M; val -= a.val; return *this;}
  inline constexpr auto& operator*=(const ModInt &a){(val *= a.val) %= M; return *this;}
  inline constexpr auto& operator/=(const ModInt &a){(val *= a.inv().val) %= M; return *this;}
 
  inline constexpr bool operator==(const ModInt &a) const {return val == a.val;}
  inline constexpr bool operator!=(const ModInt &a) const {return val != a.val;}
 
  inline constexpr auto& operator++(){*this += 1; return *this;}
  inline constexpr auto& operator--(){*this -= 1; return *this;}
 
  inline constexpr auto operator++(int){auto t = *this; *this += 1; return t;}
  inline constexpr auto operator--(int){auto t = *this; *this -= 1; return t;}
 
  inline constexpr static ModInt power(int64_t n, int64_t p){
    if(p < 0) return power(n, -p).inv();
    
    int64_t ret = 1, e = n;
    for(; p; (e *= e) %= M, p >>= 1) if(p & 1) (ret *= e) %= M;
    return ret;
  }
 
  inline constexpr static ModInt inv(int64_t a){
    int64_t b = M, u = 1, v = 0;
    
    while(b){
      int64_t t = a / b;
      a -= t * b; std::swap(a,b);
      u -= t * v; std::swap(u,v);
    }
 
    u %= M;
    if(u < 0) u += M;
    
    return u;
  }
 
  inline constexpr static auto frac(int64_t a, int64_t b){return ModInt(a) / ModInt(b);}
  
  inline constexpr auto power(int64_t p) const {return power(val, p);}
  inline constexpr auto inv() const {return inv(val);}
 
  friend inline constexpr auto operator-(const ModInt &a){return ModInt(-a.val);}
 
  friend inline constexpr auto operator+(int64_t a, const ModInt &b){return ModInt(a) + b;}
  friend inline constexpr auto operator-(int64_t a, const ModInt &b){return ModInt(a) - b;}
  friend inline constexpr auto operator*(int64_t a, const ModInt &b){return ModInt(a) * b;}
  friend inline constexpr auto operator/(int64_t a, const ModInt &b){return ModInt(a) / b;}
 
  friend std::istream& operator>>(std::istream &s, ModInt<M> &a){s >> a.val; return s;}
  friend std::ostream& operator<<(std::ostream &s, const ModInt<M> &a){s << a.val; return s;}

  template <int N>
  inline static auto div(){
    static auto value = inv(N);
    return value;
  }
};

using mint = ModInt<1000000007>;



template <typename T, typename Add = std::plus<T>, typename Minus = std::minus<T>>
class CumulativeSum1D{
  std::vector<T> data;
  const int N;
  const Add add;
  const Minus minus;
  bool is_built = false;

public:
  CumulativeSum1D(const std::vector<T> &a, const T &e = 0, const Add &add = Add(), const Minus &minus = Minus()):
    N(a.size()), add(add), minus(minus)
  {
    data.assign(N+1, e);
    for(int i = 0; i < N; ++i) data[i+1] = a[i];
  }

  CumulativeSum1D(int N, const T &e = 0, const Add &add = Add(), const Minus &minus = Minus()):
    N(N), add(add), minus(minus)
  {
    data.assign(N+1, e);
  }

  inline void update(int i, const T &val){
    assert(not is_built);
    data[i+1] = add(data[i+1], val);
  }

  inline void build(){
    assert(not is_built);
    for(int i = 0; i < N; ++i) data[i+1] = add(data[i+1], data[i]);
    is_built = true;
  }
  
  /**
   * @attention [i, j)
   */
  inline T get(int i, int j) const {
    assert(is_built);
    return minus(data[j], data[i]);
  }
};




int main(){
  int N, d, K;

  while(cin >> N >> d >> K){
    int M = N * d + 1;

    vector<mint> dp(M);

    dp[0] = 1;

    REP(i,N){
      auto s = CumulativeSum1D(dp);
      s.build();

      REP(j,M){
        dp[j] = s.get(max<int>(j-d, i), j);
      }
    }
    
    puts_all(dp[K]);
  }

  return 0;
}