Submission #1293440

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
 
#define _p(...) (void)printf(__VA_ARGS__)
#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define bit(n) (1LL<<(n))
#define sz(x) ((int)(x).size())
#define ten(n) ((int)1e##n)
#define fst first
#define snd second
using ll=long long;
using pii=pair<int,int>;using pll=pair<ll,ll>;using pil=pair<int,ll>;using pli=pair<ll,int>;
using vs=vector<string>;using vvs=vector<vs>;using vvvs=vector<vvs>;
using vb=vector<bool>;using vvb=vector<vb>;using vvvb=vector<vvb>;
using vi=vector<int>;using vvi=vector<vi>;using vvvi=vector<vvi>;
using vl=vector<ll>;using vvl=vector<vl>;using vvvl=vector<vvl>;
using vd=vector<double>;using vvd=vector<vd>;using vvvd=vector<vvd>;
using vpii=vector<pii>;using vvpii=vector<vpii>;using vvvpii=vector<vvpii>;
template<class T> bool amax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> bool amin(T &a, const T &b) { if (b < a) { a = b; return 1; } return 0; }
ll ri(){ll l;cin>>l;return l;} string rs(){string s;cin>>s;return s;}
template<class T>T read(){T t;cin>>t;return t;}
template<class T,class U>ostream&operator<<(ostream&o,const pair<T,U>&p){return o<<'('<<p.fst<<", "<<p.snd<<')';}
ostream&operator<<(ostream&o,const vb&t){forr(e,t)o<<"#."[e];return o;}
template<class T>ostream&operator<<(ostream&o,const vector<T>&t){o<<"{";forr(e,t)o<<e<<",";o<<"}"<<endl;return o;}
#ifdef LOCAL
vs s_p_l_i_t(const string&s,char c){vs v;stringstream ss(s);string x;while(getline(ss,x,c))v.emplace_back(x);return move(v);}
void e_r_r(vs::iterator it){cerr<<endl;}
template<class T,class... Args>void e_r_r(vs::iterator it,T a,Args... args){cerr<<it->substr((*it)[0]==' ',it->length())<<" = "<<a<<", ";e_r_r(++it,args...);}
#define out(args...){vs a_r_g_s=s_p_l_i_t(#args,',');e_r_r(a_r_g_s.begin(),args);}
#else
#define out(args...)
#endif
 
const int mod = 1e9+7;
template<int MOD>
struct Mint {
  int x;
  Mint() : x(0) {}
  Mint(int y) : x(y >= 0 ? y % MOD : MOD - (-y) % MOD) {}
  Mint(signed long long sll) : x(sll % MOD) { if (x < 0) x += MOD; }
  Mint &operator+=(const Mint &rhs){ if((x += rhs.x) >= MOD) x -= MOD; return *this; }
  Mint &operator-=(const Mint &rhs){ if((x += MOD - rhs.x) >= MOD) x -= MOD; return *this; }
  Mint &operator*=(const Mint &rhs){ x = 1LL*x*rhs.x % MOD; return *this; }
  Mint &operator/=(const Mint &rhs){ x = (1LL*x*rhs.inv().x) % MOD; return *this; }
  Mint operator-() const { return Mint(-x); }
  Mint operator+(const Mint &rhs) const { return Mint(*this) += rhs; }
  Mint operator-(const Mint &rhs) const { return Mint(*this) -= rhs; }
  Mint operator*(const Mint &rhs) const { return Mint(*this) *= rhs; }
  Mint operator/(const Mint &rhs) const { return Mint(*this) /= rhs; }
  bool operator<(const Mint &rhs) const { return x < rhs.x; }
  Mint inv() const {
    signed a = x, b = MOD, u = 1, v = 0, t;
    while(b){ t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); }
    return Mint(u);
  }
  Mint operator^(unsigned long long t) const {
    Mint e = *this, res = 1;
    for(; t; e *= e, t>>=1) if (t & 1) res *= e;
    return res;
  }
};
template<int MOD> ostream &operator<<(ostream &os, const Mint<MOD> &rhs) { return os << rhs.x; }
template<int MOD> istream &operator>>(istream &is, Mint<MOD> &rhs) { long long s; is >> s; rhs = Mint<MOD>(s); return is; };
 
using mint = Mint<mod>;
using vm=vector<mint>;using vvm=vector<vm>;using vvvm=vector<vvm>;
 
mint nCr[1001][1001];
void setCombi() {
  const int N = 1001;
  for (int n = 0; n < N; n++) {
    nCr[n][0] = 1;
    for (int r = 1; r <= n; r++) {
      nCr[n][r] = nCr[n - 1][r - 1] + nCr[n - 1][r];
    }
  }
}
 
mint solve() {
  int n = ri();
  int k = ri();
 
  setCombi();
 
  if (k < n) {
    return nCr[n+k-1][n-1];
  }
 
  int m = k % n;
 
  return nCr[n][m];
}
 
void Main() {
  cout << solve() << endl;
}
 
int main() { cin.tie(nullptr); ios::sync_with_stdio(false); Main(); return 0; }

Submission Info

Judge Result