枚举1-n的情况

#include <vector>
#include <algorithm>
#include <cmath>
#include <map>
#include <set>
#include<stack>
#include<queue>
using namespace std;
#define int long long
const int MOD= 998244353;
void solve() {
    int n,k;cin >> n>>k;
   vector<int> a(n+1),b(n+1);
   for(int i=1;i<=n;i++){
    cin>>a[i];
   }
   for(int i=1;i<=n;i++){
    cin>>b[i];
   }
   int ans=0,num=0,mx=0;
   for(int i=1;i<=n&&i<=k;i++){
    num+=a[i];
    mx=max(mx,b[i]);
    ans=max(ans,num+mx*(k-i));
   }
   cout<<ans<<endl;
    return;
}
signed main()
{
    iostream::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int t;cin>>t;
    while(t--){
        solve();
    }
    return 0;
}