提出 #34349419

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ソースコード 拡げる

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <algorithm>
#include <cmath>

using namespace std;

#define mp make_pair
#define pb push_back
#define ll long long

const ll mod = 998244353;

ll n;

ll poww(ll a, ll b) {
  ll ans = 1;
  while (b > 0) {
    if (b & 1) ans = (ans * a) % mod;
    b >>= 1;
    a = (a * a) % mod;
  }
  return ans;
}

ll inv(ll x) {
  return poww(x, mod - 2);
}

ll fact(ll x) {
  ll ans = 1;
  for (ll i = 1; i <= x; i++)
    ans = (ans * i) % mod;
  return ans;
}

ll catalan(ll n) {
  ll up = fact(2 * n);
  ll down = fact(n);
  down = (down * down) % mod;
  down = (down * (n + 1)) % mod;
  down = inv(down);
  return (up * down) % mod;
}

int main()
{
  cin >> n;
  ll ans = catalan(n) * poww(2, n) % mod;
  ans = ans * fact(n) % mod;
  cout << ans;

  return 0;
}

提出情報

ジャッジ結果