結果
| 問題 | 
                            No.840 ほむほむほむら
                             | 
                    
| コンテスト | |
| ユーザー | 
                             sak
                         | 
                    
| 提出日時 | 2020-07-15 20:41:29 | 
| 言語 | C++17  (gcc 13.3.0 + boost 1.87.0)  | 
                    
| 結果 | 
                             
                                AC
                                 
                             
                            
                         | 
                    
| 実行時間 | 371 ms / 4,000 ms | 
| コード長 | 2,582 bytes | 
| コンパイル時間 | 2,369 ms | 
| コンパイル使用メモリ | 207,460 KB | 
| 最終ジャッジ日時 | 2025-01-11 21:13:27 | 
| 
                            ジャッジサーバーID (参考情報)  | 
                        judge5 / judge2 | 
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| ファイルパターン | 結果 | 
|---|---|
| sample | AC * 3 | 
| other | AC * 25 | 
ソースコード
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;
template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (int i=(int)N-1; i>=0; i--)
const ll MOD = 998244353;
const ll LLINF = pow(2,61)-1;
const int INF = pow(2,30)-1;
vector<ll> fac;
void c_fac(int x=pow(10,6)+10) { fac.resize(x,true); rep(i,x) fac[i] = i ? (fac[i-1]*i)%MOD : 1; }
ll inv(ll a, ll m=MOD) { ll b = m, x = 1, y = 0; while (b!=0) { int d = a/b; a -= b*d; swap(a,b); x -= y*d; swap(x,y); } return (x+m)%m; }
ll nck(ll n, ll k) { return fac[n]*inv(fac[k]*fac[n-k]%MOD)%MOD; }
ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }
// ----------------------------------------------------------------------
// ----------------------------------------------------------------------
vector<vector<ll>> matdot(vector<vector<ll>> A, vector<vector<ll>> B) {
  if (A[0].size()!=B.size()) return {{}};
  ll h = A.size(), w = B[0].size(), x = A[0].size();
  vector<vector<ll>> result(h,vector<ll>(w,0));
  rep(i,h) rep(j,w) rep(k,x) result[i][j] = (result[i][j] + A[i][k]*B[k][j])%MOD;
  return result;
}
vector<vector<ll>> matpow(vector<vector<ll>> A, ll n) {
  if (A.size()!=A[0].size()) return {{}};
  int N = A.size();
  vector<vector<ll>> result(N,vector<ll>(N,0)), now;
  copy(all(A),back_inserter(now));
  rep(i,N) result[i][i] = 1;
  ll p2 = 1; 
  while (n>=p2) {
    if (n&p2) result = matdot(result,now);
    now = matdot(now,now); p2 *= 2;
  }
  return result;
}
// ----------------------------------------------------------------------
// ----------------------------------------------------------------------
int main() {
  ll N, K; cin >> N >> K;
  ll sn = pow(K,3);
  vector<vector<ll>> hmr(sn); rep(i,sn) hmr[i].resize(sn,0);
  rep(now,K) rep(m,K) rep(r,K) {
    ll from = now       + m       * K + r       * K*K;
    ll hto  = (now+m)%K + m       * K + r       * K*K;
    ll mto  = now       + (m+r)%K * K + r       * K*K;
    ll rto  = now       + m       * K + (r+1)%K * K*K;
    hmr[from][hto]++; hmr[from][mto]++; hmr[from][rto]++;
  }
  // rep(i,sn) debug(all(hmr[i]));
  vector<vector<ll>> hmrk = matpow(hmr, N);
  // rep(i,sn) debug(all(hmrk[i]));
  ll result = 0; rep(i,sn) if (i%K==0) result = (result+hmrk[0][i]) % MOD;
  cout << result << endl;
  return 0;
}
            
            
            
        
            
sak