#include <iostream>
#include<stdio.h>
using namespace std;
 
//long long int D[1000001], S[1000001];
 
int main() 
{
int T;
cin >> T;
while(T--)
{
long long H, A, B, IND, m;
int n;
cin >> H >> n >> m >> A >> B >> IND;
long long int D[m+1];
for(int i = 0; i < m; i++)
cin >> D[i];
long long int S[n+2];
S[0] = 0;
for(int i = 1; i <n; i++)
{
S[i] = S[i-1] + D[IND];
IND = (IND * A + B) % m;
}
double area=(S[n-1] * H);
printf("%.1lf\n",  area / 2);
}
	return 0;
}

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Mgo1CjIgMgowIDEgMAoxMCAxMAoxMAoxMCA1CjIgMyA0CjIgNSAxIDEgNA==

2
5
2 2
0 1 0
10 10
10
10 5
2 3 4
2 5 1 1 4