JT4赛时混分代码玄关求调

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int mod=998244353;
int n,a[5500],dp[5500],ans;
bool bl=1;
signed main(){
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i],bl=(bl&&(a[i]==1));
    if(n<3){cout<<"0";return 0;}
    if(n==3){
        if(a[1]+a[2]+a[3]>2*max(a[1],max(a[2],a[3]))) cout<<"1";
        else cout<<"0";
        return 0;
    }
    if(n<=21){
        for(int i=0;i<(1<<n);i++){
            int f[25]={0},k=i,maxn=-1,s=0,l=0;
            for(int j=n;j;j--){
                f[j]=k&1;
                if(k) k>>=1;
            }
            for(int j=1;j<=n;j++){
                if(f[j]) l++,maxn=max(maxn,a[j]),s+=a[j];
            }
            if(l<3) continue;
            if(s>2*maxn) ans++,ans%=mod;
        }
        cout<<ans%mod;
        return 0;
    }
    //1~10
    if(bl){
        int x=n,f=2;
        ans=1;
        while(x){
            if(x&1) ans*=f,ans%=mod;
            f*=f;x>>=1;
        }
        cout<<(((ans-1-n+mod)%mod)-n*(n-1)/2+mod)%mod;
        return 0;
    }
    //15~20
    return 0;
}