hdoj 1007 java MLE通不过

参考网上的一个算法，但是一直都是MLE，实在是想不出来什么办法了。

参考博客：编程之美寻找最近点对

import java.util.Arrays;

import java.util.Scanner;

public class Main {

    public static int N=100000;

    public static int[] list=new int[N];

    public static Point[] ptns=new Point[N];

    public static float MAX=Float.MAX_VALUE;

    public static float dis(int i,int j)

    {

        return (ptns[i].x-ptns[j].x)*(ptns[i].x-ptns[j].x)+(ptns[i].y-ptns[j].y)*(ptns[i].y-ptns[j].y);

    }

    public static float closestPair(int left,int right)

    {

        float d=MAX;

        if(left==right)

            return d;

        else if(left+1==right)

            return dis(left, right);

        int mid=(left+right)>>1;

        float d1=closestPair(left, mid);

        float d2=closestPair(mid+1, right);

        d=Math.min(d1, d2);

        int i=0,j=0,k=0;

        for(i=left;i<=right;i++)

        {

            if(Math.abs(ptns[mid].y-ptns[i].y)<d && i!=mid)

                list[k++]=i;

        }

        //对d距离内的点求最近点对

        for(i=0;i<k;i++)

        {

            for(j=i+1;j<k && Math.abs(ptns[list[j]].x-ptns[list[i]].x)<d;j++)

            {

                float dx=dis(list[i], list[j]);

                if(d>dx)

                {

                    d=dx;

                }

            }

        }

        return d;

    }

    public static void main(String[] args) {

        Scanner scanner=new Scanner(System.in);

        int n=Integer.MAX_VALUE;

        n=scanner.nextInt();

        while(n!=0)

        {

            for(int i=0;i<n;i++)

            {

                Point point=new Point();

                point.x=scanner.nextFloat();

                point.y=scanner.nextFloat();

                ptns[i]=point;

            }

            Arrays.sort(ptns,0,n-1);

            System.out.println(String.format("%.2f",Math.sqrt(closestPair(0, n-1))/2));

            n=scanner.nextInt();

        }

        scanner.close();

    }

    static class Point implements Comparable<Point>

    {

        public float x;

        public float y;

        @Override

        public int compareTo(Point o) {

            // TODO Auto-generated method stub

            if(this.y>o.y)

                return 1;

            else if(this.y<o.y)

                return -1;

            else 

            {

                if(this.x>o.x)

                    return 1;

                else if(this.x<o.x)

                    return -1;

                return 0;

            }

        }    

    }

}