算法提高 最大乘积

import java.io.BufferedInputStream;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(new BufferedInputStream(System.in));
        int num =in.nextInt();
        int max = 1;
        int i,j,k;
        for ( i = 0 ; i < num ; i++ ){
            max = 1;
            int n = in.nextInt();
            int m = in.nextInt();
            int[] a = new int[n];
            for (j = 0 ; j < n ; j++){
                a[j] = in.nextInt();
            }
            Arrays.sort(a);
            int s1,s2;
            for ( j = 0 ,k = n-1 ; m > 0 ;){
                if ( m >= 2){
                    s1 = a[j] * a[j+1];
                    s2 = a[k] * a[k-1];
                    if ( s1 >= s2){
                        max *= s1;
                        j = j+2;
                        m -= 2;
                    }else{
                        max *= a[k];
                        k--;
                        m--;
                    }
                }else{
                    max *= a[k];
                    j--;
                    m--;
                }
            }
            System.out.println(max);
        }
        in.close();
    }

}