D - Nails

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

#define int long long
const int N = 1e3 + 5;
const int mod = 1e9 + 7;
const int INF = 1e18;
int dp[N][5];

signed main()
{
    int n;
    cin >> n;
    vector<int> a(n);
    for(int i = 0; i < n; i++){
        cin >> a[i];
    }
    sort(a.begin() , a.end());
    dp[1][1] = a[1] - a[0];
    dp[1][0] = INF;
    for(int i = 2; i < n; i++){
        dp[i][0] = dp[i - 1][1];
        dp[i][1] = min(dp[i - 1][0] , dp[i - 1][1]) + a[i] - a[i - 1];
    }
    cout << dp[n - 1][1] << endl;
}