题解 | 画展布置

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int m = in.nextInt();
        long[] a = new long[n+1]; //结果最大值1e10-1>INT_MAX
        for(int i=1; i<=n; i++) a[i] = in.nextInt();
        Arrays.sort(a);
        long ans = 1000000000000L;
        for(int i=1; i+m-1<=n; i++){
            ans = Math.min(ans, a[i+m-1]*a[i+m-1]-a[i]*a[i]);
        }
        System.out.println(ans);
    }
}