Codeforces Round #527 (Div. 3) B. Teams Forming(水题)

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

int main()
{
	int n;
  int pre[105];
  cin>>n;
  for(int i=0;i<n;i++){
    cin>>pre[i];
  }
  sort(pre,pre+n);
  int a = 0;
  for(int i=1;i<n;i+=2){
    a += pre[i] - pre[i-1];
  }
  cout<<a<<endl;
	return 0;
}