Why does this code fail subtask 2(FROGS)

#include<bits/stdc++.h>
using namespace std;
int main()
{
int l[5],w[4],t,n,i,sum,j,sml1,str,index;
cin>>t;
while(t–)
{
sum=0;
sml1=5;
index=0;
cin>>n;
for(i=0;i<n;i++)
{
cin>>w[i];
if(w[i]<sml1)
{
sml1=w[i];
str=i;
}
}
for(i=0;i<n;i++)
{
cin>>l[i];
}
for(i=sml1+1;i<=n;i++)
{
for(j=0;j<n;j++)
{
if(w[j]==i)
{
index=j;
if(j<str)
{
while(index<=str)
{
index=index+l[j];
sum++;
}
}
str=index;
}
}
}
cout<<sum<<endl;
}
}