#include<bits/stdc++.h>
#define ll long long
using namespace std;
int now,las;
ll s[1000010];
vector<pair<ll,ll> >p;
vector<long double>v;
ll calc(int x,ll y){
	return p[x].first*y+p[x].second;
}
ll query(ll x){
	while(las+1<v.size()&&v[las+1]<=x){
		las++;
	}
	return las<v.size()?calc(las,x):0;
}
long double intersect(ll a,ll b,ll c,ll d){
	return 1.0*(b-d)/(c-a);
}
void update(ll x,ll y){
	while(now>=2&&intersect(x,y,p[now-1].first,p[now-1].second)<=intersect(p[now-1].first,p[now-1].second,p[now-2].first,p[now-2].second)){
		now--;
		p.pop_back();
		v.pop_back();
	}
	v.push_back(now>=1?intersect(x,y,p[now-1].first,p[now-1].second):-1e18);
	p.push_back({x,y});
	now++;
}
int main(){
	int t,n;
	ll ans,a,b,c,x;
	scanf("%d",&t);
	while(t--){
		p.clear();
		v.clear();
		now=las=0;
		scanf("%d%lld%lld%lld",&n,&a,&b,&c);
		update(0,0);
		for(int i=1;i<=n;i++){
			scanf("%lld",&x);
			s[i]=s[i-1]+x;
			ans=query(s[i])+a*s[i]*s[i]+b*s[i]+c;
			update(-2*a*s[i],a*s[i]*s[i]-b*s[i]+ans);
		}
		printf("%lld\n",ans);
	}
}