#include<iostream>#include<cstring>#include<cstdio>#include<algorithm>#include<cmath>using namespace std;int n,k;double a[1005],dp[1005][1005];int main(){    int T;    scanf("%d",&T);    while(T--)    {        scanf("%d%d",&n,&k);        for(int i = 1;i <= n;i++)    scanf("%lf",&a[i]);        dp[1][0] = 1-a[1];        dp[1][1] = a[1];        for(int i = 2;i <= n;i++)        {            for(int k = 0;k <= n;k++)            {                if(k == 0)    dp[i][k] = dp[i-1][k]*(1-a[i]);                else        dp[i][k] = dp[i-1][k]*(1-a[i])+dp[i-1][k-1]*a[i];            }        }        double ans = 0;        for(int i = k;i <= n;i++)    ans += dp[n][i];        printf("%.4f\n",ans);    }    return 0;}