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;
            }
        }    
    }
}