就是用树状数组优化了，然后根据公式搞，然后就WA。

//2021.3.19 
#include<bits/stdc++.h>
using namespace std;
#define ll long long
ll n,ans,fac[1000010],tree[1000010];
const ll mod=998244353;
ll lowbit(ll x){
	return x&-x;
}
void add(ll id,ll val){
	for(;id<=n;id+=lowbit(id)) tree[id]+=val;
}
ll ask(ll id){
	ll res=0;
	for(;id;id-=lowbit(id)) res+=tree[id];
	return res;
}
void Fac(){
	fac[0]=1;
	for(ll i=2;i<=n;i++){
		fac[i]=fac[i-1]*i%mod;
		add(i,1);
	}
}
int main(){
	scanf("%lld",&n);
	Fac();
	for(ll i=1;i<=n;i++){
		ll x;
		scanf("%lld",&x);
		ans=(ans+(ask(x)-1)*fac[n-i])%mod;
		add(x,-1);
	}
	printf("%lld",ans+1);
	return 0;
}  

求助，谢谢