贪心senior‘s GUN

#include<bits/stdc++.h>
using namespace std;

const int Max=100000;
int a[Max];
int b[Max];

bool Compare(int x,int y){
    return x>y;
}

int main(){
    int t;;
    cin>>t;
    while(t--){
        int n,m;
        while(cin>>n>>m){
            for(int i=0;i<n;i++){
                cin>>a[i];
            }
            for(int i=0;i<m;i++){
                cin>>b[i];
            }
            sort(a,a+n,Compare);
            sort(b,b+m);
            long long answer=0;
            for(int i=0;i<n;i++){
                if(a[i]>b[i]||i<=m){
                    answer+=a[i]-b[i];
                }
                else{
                    break;
                }
            }
            cout<<answer<<endl;
        }
    }
    return 0;
}