1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cmath>
 6 using namespace std;
 7 int rd(){int z=0,mk=1;  char ch=getchar();
 8     while(ch<'0'||ch>'9'){if(ch=='-')mk=-1;  ch=getchar();}
 9     while(ch>='0'&&ch<='9'){z=(z<<3)+(z<<1)+ch-'0';  ch=getchar();}
10     return z*mk;
11 }
12 int n,m,nn,mm,a[2100],b[2100];  double p[2100];
13 int e[310][310];
14 double f[2100][2100][2];
15 void floyd(){
16     for(int k=1;k<=nn;++k)for(int i=1;i<=nn;++i)for(int j=1;j<=nn;++j)
17         if(e[i][k]+e[k][j]<e[i][j])  e[i][j]=e[i][k]+e[k][j];
18 }
19 int main(){//freopen("ddd.in","r",stdin);
20     memset(e,10,sizeof(e));
21     cin>>n>>m>>nn>>mm;
22     for(int i=1;i<=n;++i)  a[i]=rd();
23     for(int i=1;i<=n;++i)  b[i]=rd();
24     for(int i=1;i<=n;++i)  scanf("%lf",&p[i]);
25     int l,r,v;
26     while(mm--){  l=rd(),r=rd(),v=rd();  e[l][r]=e[r][l]=min(v,e[l][r]);}
27     for(int i=1;i<=nn;++i)  e[i][i]=0;
28     floyd();
29     for(int i=1;i<=n;++i)for(int j=0;j<=m;++j)  f[i][j][0]=f[i][j][1]=1e30;
30     f[1][0][0]=f[1][1][1]=0;
31     for(int i=2;i<=n;++i)for(int j=0;j<=m;++j){
32         f[i][j][0]=min(f[i-1][j][0]+e[a[i-1]][a[i]],f[i-1][j][1]+e[a[i-1]][a[i]]*(1-p[i-1])+e[b[i-1]][a[i]]*p[i-1]);
33         if(j>=1){
34             f[i][j][1]=min(f[i][j][1],f[i-1][j-1][0]+e[a[i-1]][a[i]]*(1-p[i])+e[a[i-1]][b[i]]*p[i]);
35             f[i][j][1]=min(f[i][j][1],f[i-1][j-1][1]+e[a[i-1]][a[i]]*(1-p[i-1])*(1-p[i])+e[a[i-1]][b[i]]*(1-p[i-1])*p[i]
36                 +e[b[i-1]][a[i]]*p[i-1]*(1-p[i])+e[b[i-1]][b[i]]*p[i-1]*p[i]);
37         }
38     }
39     double ans=1e30;
40     for(int i=0;i<=m;++i)  ans=min(ans,min(f[n][i][0],f[n][i][1]));
41     printf("%.2lf\n",ans);
42     return 0;
43 }