样例全过了

#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 2e5 + 5,M = 998244353;
int n,a[N],cnt[N],pre[2 * N],ans;
bool f[N];
int A(int x,int y){
	int mul = 1;
	for (int i = 1; i <= y; i++){
		mul = (mul * x) % M;
		x--;
	}
	return mul;
}
int C(int x,int y){return (A(x,y) / A(y,y)) % M;}
signed main(){
	cin >> n;
	for (int i = 1; i <= n; i++){
		cin >> a[i];
		cnt[a[i]]++;
	}
	sort(a + 1,a + n + 1);
	for (int i = 1; i <= N - 5; i++) pre[i] = pre[i - 1] + cnt[i];
	for (int i = 1; i <= n; i++){
		if (cnt[a[i]] < 2 || f[a[i]]) continue;
		int c = C(cnt[a[i]],2),c2 = C(cnt[a[i]],3);
		ans = (ans + c * (pre[a[i] * 2 - 1] - cnt[a[i]]) + c2) % M;
		f[a[i]] = 1;
//		cout << c << ' ' << t << ' ' << cnt[a[i]] << ' ' << c2 << ' ' << ans << "\n";
	}
	cout << ans;
	return 0;
}