贪心

#include <iostream>
#include <algorithm>
#include <cmath>
using namespace std;
const int N = 1E5 + 10;
typedef long long ll;
int ads[N];
int main(){
    int n;  cin >> n;
    for(int i = 0; i < n; i ++ )    cin >> ads[i];
    sort(ads, ads + n);
    ll res = 0;
    for(int i = 0; i < n; i ++ )    res += abs(ads[n / 2] - ads[i]);
    cout << res << endl;
    return 0;
}