CF997C

数组没开够竟然是TLE…

#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

ll n,ans;
const int mod=998244353;

int qpow(ll a,ll b){
    int ret=1;
    for(;b;b>>=1,a=1ll*a*a%mod)if(b&1)ret=1ll*ret*a%mod;
    return ret;
}
int inv(int x){return qpow(x,mod-2);}
int fact[(int)1e6+9],inv_fact[(int)1e6+9];
int C(int n,int m){
    if(m>n||n<0||m<0)return 0;
    return 1ll*fact[n]*inv_fact[m]%mod*inv_fact[n-m]%mod;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin>>n;
    fact[0]=1;
    f(i,1,n)fact[i]=1ll*fact[i-1]*i%mod;
    inv_fact[n]=inv(fact[n]);
    for(int i=n-1;i>=0;i--)inv_fact[i]=1ll*inv_fact[i+1]*(i+1)%mod;
    
    ll invc=inv(3);
    for(int i=1;i<=n;++i){
        ans=(ans+(i&1?1ll:-1ll)*C(n,i)*qpow(invc,i*n)%mod*(qpow(1+mod-qpow(invc,n-i),n)-1)%mod+mod)%mod;
    }
    ans=1ll*qpow(3,n*n+1)*ans%mod;
    for(int i=1;i<=n;++i){
        ans=(ans+(i&1?2ll:-2ll)*C(n,i)*qpow(3,i)%mod*qpow(3ll,n*(n-i))%mod+mod)%mod;
    }
    cout<<ans;
    return 0;
}