two arrays and swap

#include<bits/stdc++.h>
using namespace std;
int main()
{

 int t;
 cin>>t;
 while(t--)
 {
   int n,k,sum=0;
   cin>>n>>k;
   int arr1[n];
   int arr2[n];
   for(int i=0;i<n;i++)
   {
       cin>>arr1[i];

   }
   for(int j=0;j<n;j++)
   {
       cin>>arr2[j];

   }
   if(k==0)
   {

      cout<< accumulate(arr1, arr1+n,sum)<<endl;;

   }
   else{
       sort(arr1,arr1+n);
       sort(arr2, arr2 + n, greater<int>());

       for(int i=0;i<k;i++)
       {
           if(arr1[i]<arr2[i])
           {
               arr1[i]=arr2[i];
           }
       }
       cout<<accumulate(arr1, arr1+n,sum)<<endl;


   }

 }


}