結果

問題 No.802 だいたい等差数列
ユーザー momoharamomohara
提出日時 2024-04-13 14:44:03
言語 C++23
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 66 ms / 2,000 ms
コード長 5,855 bytes
コンパイル時間 4,884 ms
コンパイル使用メモリ 320,744 KB
実行使用メモリ 26,336 KB
最終ジャッジ日時 2024-10-03 00:08:19
合計ジャッジ時間 7,011 ms
ジャッジサーバーID
(参考情報)
judge4 / judge3
このコードへのチャレンジ
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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 <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;
template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;
#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
#define rep(i, m, n) for(ll i = (ll)(m); i < (ll)(n); ++i)
#define rep2(i, m, n) for(ll i = (ll)(n)-1; i >= (ll)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)
constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
// constexpr long long MOD = 998244353LL;
static const ld pi = 3.141592653589793L;
#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
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;
}
struct Edge {
int to, rev;
ll cap;
Edge(int _to, int _rev, ll _cap) : to(_to), rev(_rev), cap(_cap) {}
};
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
void add_edge(Graph &G, int from, int to, ll cap, bool revFlag, ll revCap) {
G[from].push_back(Edge(to, (int)G[to].size(), cap));
if(revFlag)
G[to].push_back(Edge(from, (int)G[from].size() - 1, revCap));
}
template <int mod>
struct ModInt {
int x;
ModInt() : x(0) {}
ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}
ModInt &operator+=(const ModInt &p) {
if((x += p.x) >= mod)
x -= mod;
return *this;
}
ModInt &operator-=(const ModInt &p) {
if((x += mod - p.x) >= mod)
x -= mod;
return *this;
}
ModInt &operator*=(const ModInt &p) {
x = (int)(1LL * x * p.x % mod);
return *this;
}
ModInt &operator/=(const ModInt &p) {
*this *= p.inverse();
return *this;
}
ModInt operator-() const { return ModInt(-x); }
ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }
ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }
ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }
ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }
bool operator==(const ModInt &p) const { return x == p.x; }
bool operator!=(const ModInt &p) const { return x != p.x; }
ModInt inverse() const {
int a = x, b = mod, u = 1, v = 0, t;
while(b > 0) {
t = a / b;
swap(a -= t * b, b);
swap(u -= t * v, v);
}
return ModInt(u);
}
ModInt pow(int64_t n) const {
ModInt ret(1), mul(x);
while(n > 0) {
if(n & 1)
ret *= mul;
mul *= mul;
n >>= 1;
}
return ret;
}
friend ostream &operator<<(ostream &os, const ModInt &p) {
return os << p.x;
}
friend istream &operator>>(istream &is, ModInt &a) {
int64_t t;
is >> t;
a = ModInt<mod>(t);
return (is);
}
static int get_mod() { return mod; }
};
using mint = ModInt<MOD>;
template <class T>
struct Combination {
vector<T> fact_, inv_, finv_;
constexpr Combination() {}
constexpr Combination(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
init(n + 1);
}
constexpr void init(int n) noexcept {
fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
int MOD = fact_[0].get_mod();
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 nPr(int n, int k) const noexcept {
if(n < k || n < 0 || k < 0)
return 0;
return fact_[n] * finv_[n - k];
}
constexpr T nCr(int n, int k) const noexcept {
if(n < k || n < 0 || k < 0)
return 0;
if(n < MOD)
return fact_[n] * finv_[k] * finv_[n - k];
// Lucas
T ret = 1;
while(n || k) {
ll _n = n % MOD, _k = k % MOD;
n /= MOD;
k /= MOD;
ret *= nCr(_n, _k);
}
return ret;
}
constexpr T nHr(int n, int k) const noexcept {
if(n <= 0 || k < 0)
return 0;
return nCr(n + k - 1, k);
}
constexpr T fact(int n) const noexcept {
if(n < 0)
return 0;
return fact_[n]; // n!
}
constexpr T inv(int n) const noexcept {
if(n < 0)
return 0;
return inv_[n]; // 1/n
}
constexpr T finv(int n) const noexcept {
if(n < 0)
return 0;
return finv_[n]; // 1/n!
}
};
void solve() {
ll n, m, d1, d2;
cin >> n >> m >> d1 >> d2;
Combination<mint> com(n + m);
// f=(x^D1-x^(D2+1))^(N-1)
vec<mint> f(m + 1, 0);
REP(i, n) {
ll k = d1 * (n - 1 - i) + (d2 + 1) * i;
if(k > m)
continue;
if(i % 2)
f[k] -= com.nCr(n - 1, i);
else
f[k] += com.nCr(n - 1, i);
}
// g=(1-x)^(-N-1)
vec<mint> g(m + 1, 0);
REP(i, m + 1) {
g[i] = com.nCr(n + i, n);
}
mint ans = 0;
REP(i, m) {
ll j = m + 1 - i - 2;
ans += f[i] * g[j];
}
cout << ans << en;
}
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
// cout << fixed << setprecision(10);
// ll t;
// cin >> t;
// REP(i, t - 1) {
// solve();
// }
solve();
return 0;
}
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