結果

問題 No.2383 Naphthol
ユーザー umimel
提出日時 2023-07-14 23:01:27
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 146 ms / 2,000 ms
コード長 4,902 bytes
コンパイル時間 1,698 ms
コンパイル使用メモリ 168,812 KB
実行使用メモリ 15,608 KB
最終ジャッジ日時 2024-09-16 08:09:16
合計ジャッジ時間 5,658 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
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ファイルパターン 結果
sample AC * 3
other AC * 18
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 <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60;
const int IINF = 1 << 30 - 1;
template<typename T> struct Edge{
    int to; T w;
    Edge(int to_, T w_=1){
        to = to_;
        w=w_;
    }
};
template<typename T> using Tree = vector<vector<Edge<T>>>;
template<typename T> using Graph = vector<vector<Edge<T>>>;
/* 容量&重み付きエッジ for Dinic */
template<typename T> struct REdge{
    int to;
    T cap;
    T cost;
    int rev;
    REdge(int to_, T cap_, T cost_=1){
        to = to_;
        cap = cap_;
        cost = cost_;
    }
    
    REdge(int to_, T cap_, T cost_, int rev_){
        to = to_;
        cap = cap_;
        cost = cost_;
        rev = rev_;
    }
};
/* 残余グラフ for Dinic */
template<typename T> using RGraph = vector<vector<REdge<T>>>;
template<long long mod>
class modint{
    long long x;
public:
    modint(long long x=0) : x((x%mod+mod)%mod) {}
    modint operator-() const { 
      return modint(-x);
    }
    bool operator==(const modint& a){
        if(x == a) return true;
        else return false;
    }
    bool operator==(long long a){
        if(x == a) return true;
        else return false;
    }
    bool operator!=(const modint& a){
        if(x != a) return true;
        else return false;
    }
    bool operator!=(long long a){
        if(x != a) return true;
        else return false;
    }
    modint& operator+=(const modint& a) {
        if ((x += a.x) >= mod) x -= mod;
        return *this;
    }
    modint& operator-=(const modint& a) {
        if ((x += mod-a.x) >= mod) x -= mod;
        return *this;
    }
    modint& operator*=(const  modint& a) {
        (x *= a.x) %= mod;
        return *this;
    }
    modint operator+(const modint& a) const {
        modint res(*this);
        return res+=a;
    }
    modint operator-(const modint& a) const {
        modint res(*this);
        return res-=a;
    }
    modint operator*(const modint& a) const {
        modint res(*this);
        return res*=a;
    }
    modint pow(long long t) const {
        if (!t) return 1;
        modint a = pow(t>>1);
        a *= a;
        if (t&1) a *= *this;
        return a;
    }
    // for prime mod
    modint inv() const {
        return pow(mod-2);
    }
    modint& operator/=(const modint& a) {
        return (*this) *= a.inv();
    }
    modint operator/(const modint& a) const {
        modint res(*this);
        return res/=a;
    }
    friend std::istream& operator>>(std::istream& is, modint& m) noexcept {
        is >> m.x;
        m.x %= mod;
        if (m.x < 0) m.x += mod;
        return is;
    }
    friend ostream& operator<<(ostream& os, const modint& m){
        os << m.x;
        return os;
    }
};
using mint = modint<MOD998244353>;
const ll MAX = 510000;
mint fac[MAX], finv[MAX], inv[MAX];
 
void cominit(){
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for(ll i=2; i<MAX; i++){
        fac[i] = fac[i-1] * i;
        inv[i] = mint(i).inv();
        finv[i] = finv[i-1] * inv[i];
    }
}
 
mint com(ll n, ll k){
    if(n < k) return 0;
    if(n < 0 || k < 0) return mint(0);
    return fac[n] * finv[k] * finv[n-k];
}
int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    cominit();
    ll n, k; cin >> n >> k;
    if(n>1){
        mint ans = 0;
        if(k%2==0){
            ans += com(2*n+4, k);
            //180度回転
            ans += com(n+2, k/2);
            //反転
            if(n%2==1){
                //(上中央, 下中央)=(塗らない, 塗らない)
                if(k <= 2*n+2) ans += com(n+1, k/2);
                //(上中央, 下中央)=(塗る, 塗る)
                if(k-2 <= 2*n+2) ans += com(n+1, (k-2)/2);
            }else{
                ans += com(n+2, k/2);
            }
            //反転+180度回転
            ans += com(n+2, k/2);
        }else{
            ans = com(2*n+4, k);
            //反転
            if(n%2==1){
                //(上中央, 下中央)=(塗る, 塗らない)
                if(k-1 <= 2*n+2) ans += com(n+1, (k-1)/2);
                //(上中央, 下中央)=(塗らない, 塗る)
                if(k-1 <= 2*n+2) ans += com(n+1, (k-1)/2);
            }
        }
        ans /= 4;
        cout << ans << endl;
    }else{
        mint ans = 0;
        if(k==6 || k==1 || k==5){
            cout << 1 << endl;
        }else if(k==2 || k==4 || k==3){
            cout << 3 << endl;
        }
    }
}
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