結果

問題 No.802 だいたい等差数列
ユーザー goodbaton
提出日時 2019-03-18 08:58:24
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 69 ms / 2,000 ms
コード長 2,996 bytes
コンパイル時間 990 ms
コンパイル使用メモリ 102,764 KB
実行使用メモリ 23,552 KB
最終ジャッジ日時 2024-07-17 21:20:35
合計ジャッジ時間 3,113 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge2
このコードへのチャレンジ
（要ログイン）
ファイルパターン 結果
sample AC * 4
other AC * 30
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <iostream>
#include <complex>
#include <string>
#include <algorithm>
#include <numeric>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <functional>
#include <cassert>
typedef long long ll;
using namespace std;
#ifndef LOCAL
#define debug(x) ;
#else
#define debug(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl;
template <typename T1, typename T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}
template <typename T>
ostream &operator<<(ostream &out, const vector<T> &v) {
  out << '{';
  for (const T &item : v) out << item << ", ";
  out << "\b\b}";
  return out;
}
#endif
#define mod 1000000007 //1e9+7(prime number)
#define INF 1000000000 //1e9
#define LLINF 2000000000000000000LL //2e18
#define SIZE 200010
vector<ll> factmemo, factmemoInv;
ll factmemoMod = -1;
ll factorial(int n, int M){
  if(factmemoMod == M) return factmemo[n];
  if(n <= 1) return 1;
  ll res = 1;
  for(int i=1; i<=n; i++) res = res * i % M;
  return res;
}
ll power(int k, int n, int M){
  if(n == 0) return 1;
  if(n == 1) return (ll)k;
  ll res = power(k, n/2, M);
  res = res * res % M;
  return n%2 == 1 ? res * k % M : res;
}
void initFactorial(int n, int M){
  factmemo.assign(n+1, 0);
  factmemoInv.assign(n+1, 0);
  factmemoMod = M;
  factmemo[0] = 1;
  for(int i=1;i<=n;i++) factmemo[i] = factmemo[i-1] * i % M;
  factmemoInv[n] = power(factmemo[n], M-2, M);
  for(int i=n;i>0;i--) factmemoInv[i-1] = factmemoInv[i] * i % M;
}
//nCm nPm nHm (mod M)
/*Combination*/
ll C(int n, int m, int M){
  if(n < m) return 0;
  if(m == 0 || n == m) return 1;
  if(factmemoMod == M)
    return factmemo[n] * factmemoInv[m] % M * factmemoInv[n-m] % M;
  ll numer = factorial(n, M);
  ll denom = factorial(m, M) * factorial(n-m, M) % M;
  denom = power((int)denom, M-2, M);
  return numer * denom % M;
}
/*Permutation*/
ll P(int n, int m, int M){
  if(n < m) return 0;
  if(m == 0) return 1;
  if(factmemoMod == M)
    return factmemo[n] * factmemoInv[n-m] % M;
  ll numer = factorial(n, M);
  ll denom = factorial(n-m, M);
  denom = power((int)denom, M-2, M);
  return numer * denom % M;
}
/*Combination with Repetitions*/
ll H(int n, int m, int M){
  if(n == 0 && m == 0) return 1;
  return C(n+m-1, m, M);
}
int main(){
  ll N, M, D1, D2;
  cin >> N >> M >> D1 >> D2;
  initFactorial(N + M, mod);
  if(M < D1 * (N - 1)) {
    cout << 0 << endl;
    return 0;
  }
  M --;
  M -= D1 * (N - 1);
  D2 -= D1;
  ll ans = 0;
  int sign = 1;
  debug(M); debug(D2);
  for(int i=0;i<N;i++){
    ll m = M - (D2 + 1) * i;
    if(m < 0) break;
    ll p = C(m + N, N, mod);
    ll q = C(N-1, i, mod);
    debug(p); debug(q);
    ans += (mod + sign * p * q % mod) % mod;
    sign *= -1;
  }
  cout << ans % mod << endl;
  return 0;
}
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
0