#define all(a) (a).begin(), (a).end()

int maxMin(int k, vector<int> arr) {
    sort(all(arr));
    
    int n = arr.size();
    int best = 1e9;
    for (int i = 0; i <= n-k; i++) {
        best = min(best, arr[k-1+i]-arr[i]);
    }
    return best;
}