#900342 (C++17) No.2409 Strange Werewolves

• 問題: No.2409 Strange Werewolves
• ユーザー: 👑 Nachia
• 提出日時: 2023-08-11 21:31:18
• 言語: C++17 (gcc 13.3.0 + boost 1.87.0)
• 結果: AC
• 実行時間: 9 ms / 2,000 ms
• コード長: 2,360 bytes
• コンパイル時間: 685 ms
• コンパイル使用メモリ: 80,956 KB
• 最終ジャッジ日時: 2025-02-16 01:04:31
• ジャッジサーバーID （参考情報）: judge3 / judge5

ファイルパターン	結果
sample	AC * 2
other	AC * 16

ソースコード

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#line 1 "..\\Main.cpp"
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <atcoder/modint>
#line 3 "D:\\Programming\\VSCode\\competitive-cpp\\nachia\\math\\combination.hpp"
namespace nachia{
template<class Modint>
class Comb{
private:
    static constexpr int MOD = Modint::mod();
    std::vector<Modint> F;
    std::vector<Modint> iF;
public:
    void extend(int newN){
        int prevN = (int)F.size() - 1;
        if(newN >= MOD) newN = MOD - 1;
        if(prevN >= newN) return;
        F.resize(newN+1);
        iF.resize(newN+1);
        for(int i=prevN+1; i<=newN; i++) F[i] = F[i-1] * Modint::raw(i);
        iF[newN] = F[newN].inv();
        for(int i=newN; i>prevN; i--) iF[i-1] = iF[i] * Modint::raw(i);
    }
    Comb(int n = 1){
        F.assign(2, Modint(1));
        iF.assign(2, Modint(1));
        extend(n);
    }
    Modint factorial(int n) const { return F[n]; }
    Modint invFactorial(int n) const { return iF[n]; }
    Modint invOf(int n) const { return iF[n] * F[n-1]; }
    Modint comb(int n, int r) const {
        if(n < 0 || n < r || r < 0) return Modint(0);
        return F[n] * iF[r] * iF[n-r];
    }
    Modint invComb(int n, int r) const {
        if(n < 0 || n < r || r < 0) return Modint(0);
        return iF[n] * F[r] * F[n-r];
    }
    Modint perm(int n, int r) const {
        if(n < 0 || n < r || r < 0) return Modint(0);
        return F[n] * iF[n-r];
    }
    Modint invPerm(int n, int r) const {
        if(n < 0 || n < r || r < 0) return Modint(0);
        return iF[n] * F[n-r];
    }
    Modint operator()(int n, int r) const { return comb(n,r); }
};
} // namespace nachia
#line 8 "..\\Main.cpp"
using namespace std;
using i32 = int;
using u32 = unsigned int;
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
const i64 INF = 1001001001001001001;
using Modint = atcoder::static_modint<998244353>;
int main(){
    int X,Y,Z,W; cin >> X >> Y >> Z >> W;
    nachia::Comb<Modint> comb(X+Y);
    Modint t = comb(X,Z) * comb(Y,W);
    if(Z == 0){ swap(Z,W); swap(X,Y); }
    Modint ans = t * comb.factorial(X+Y-Z) * Y / (X+Y-Z);
    cout << ans.val() << endl;
    return 0;
}
struct ios_do_not_sync{
    ios_do_not_sync(){
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} ios_do_not_sync_instance;
 
 
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