C++ :

#include<iostream>
#include<cstring>
#include<cstdio>
#include<cmath>
using namespace std;
int a[10010],b[10010];
int n;
void init();
void maopao(int a[]);
void work();
int main()
{
	init();
	work();
	return 0;
}
void init()
{
	//freopen("test0.in","r",stdin);
	cin>>n;
	for(int i=1;i<=n;++i)cin>>a[i];
	for(int i=1;i<=n;++i)cin>>b[i];
}
void maopao(int a[])
{
	int temp,k;
	for(int i=1;i<=n;i++)
	{
		temp=a[i];
		k=i;
		for(int j=i;j<=n;j++)
		{
			if(temp>a[j])
			{
				temp=a[j];
				k=j;
			}
		}
		temp=a[i];
		a[i]=a[k];
		a[k]=temp;
	}
}
void work()
{
	maopao(a);
	maopao(b);
	int sum=0;
	int d;
	for(int i=1;i<=n;++i)
	{
		if(a[i]<b[n-i+1])d=b[n-i+1]-a[i];
		else d=a[i]-b[n-i+1];
		sum+=d;
	}
	cout<<sum<<endl;
}

Pascal :

type
  arr=array[1..10000]of longint;


var
 n,i,ans:longint;
 a,b:arr;


procedure readdata;
var
 i:longint;
begin
 readln(n);
 for i:=1 to n do
  read(a[i]);
 for i:=1 to n do
  read(b[i]);
end;


procedure qsort1(var a:arr;l,r: longint);
var
   i,j,x,y: longint;
begin
   i:=l;
   j:=r;
   x:=a[(l+r) shr 1];
   repeat
    while a[i]<x do
      inc(i);
    while x<a[j] do
      dec(j);
    if not(i>j) then
     begin
       y:=a[i];a[i]:=a[j];a[j]:=y;
       inc(i);dec(j);
     end;
  until i>j;
  if l<j then
    qsort1(a,l,j);
  if i<r then
    qsort1(a,i,r);
end;


procedure qsort2(var a:arr;l,r: longint);
var
   i,j,x,y: longint;
begin
   i:=l;
   j:=r;
   x:=a[(l+r) shr 1];
   repeat
    while a[i]>x do
      inc(i);
    while x>a[j] do
      dec(j);
    if not(i>j) then
     begin
       y:=a[i];a[i]:=a[j];a[j]:=y;
       inc(i);dec(j);
     end;
  until i>j;
  if l<j then
    qsort2(a,l,j);
  if i<r then
    qsort2(a,i,r);
end;


function abss(x:longint):longint;
begin
 if x<0 then exit(-x);
 exit(x);
end;


procedure greedy;
var
 i:longint;
begin
  qsort1(a,1,n);
  qsort2(b,1,n);
  for i:=1 to n do
   inc(ans,abss(a[i]-b[i]));
end;


begin
  readdata;
  greedy;
  writeln(ans);
end.