Submission #34350536

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Source Code Expand

#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 n) {
  ll ans = 1;
  for (ll i = 2; i <= n; i++)
    ans = (ans * i) % mod;
  return ans;
}

ll comb(ll n, ll k) {
  ll up = fact(n);
  ll down = (fact(k) * fact(n - k)) % mod;
  return (up * inv(down)) % mod;
}

int main()
{
  cin >> n;

  ll ans = (n * n) % mod;
  ans = (ans * comb(n * n, 2 * n - 1)) % mod;
  ans = (ans * fact(n - 1)) % mod;
  ans = (ans * fact(n - 1)) % mod;
  ans = (ans * fact(n * n - 2 * n + 1)) % mod;
  ans = (fact(n * n) + mod - ans) % mod;
  cout << ans;



  return 0;
}

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