第k选择

package untitled;
import java.util.Random;
import java.util.Scanner;
public class dk {
    public static void main(String[] args) {
        Random rand=new Random();
        int[] r=new int [2000];
        System.out.print("参与选择的有n个整数,请确定n:");
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        System.out.print("选择第k小整数,请确定k:");
        int k=sc.nextInt();
        sc.close();
        for(int i=0;i<n;i++)
        {
            r[i]=rand.nextInt(100);
            System.out.print(r[i]+" ");
        }
        System.out.println();
        yhy(r, 1, n, k);
        System.out.print("以上"+n+"个整数中第"+k+"小整数为"+r[k]);
    }
    public static int yhy(int[] r,int m1,int m2,int m) {
        int i,j;
        if(m1<m2){
            i=m1;
            j=m2;
            r[0]=r[i];
            while(i!=j){
                while(r[j]>=r[0]&&j>i)
                    j=j-1;
                if(i<j) {r[i]=r[j];i=i+1;}
                while(r[i]<=r[0]&&j>i)
                    i=i+1;
                if(i<j) {r[j]=r[i];j=j-1;}
            }
            r[i]=r[0];
            if(i==m)
                return r[m];
            else if(i>m)
                return yhy(r, m1, i-1, m);
            else
                return yhy(r, i+1, m2, m);
        }
        else return 0;
    }
}