BigDecimal操作（开方+牛顿迭代法）

import java.io.*;
import java.util.*;
import java.math.*;

class Main  
{
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner cin=new Scanner(System.in);
        BigDecimal a,b,maxn,minn,k,res;
        BigDecimal one=new BigDecimal("1");
        BigDecimal five=new BigDecimal("5");
        BigDecimal two=new BigDecimal("2");
        while(cin.hasNext()){
            a=cin.nextBigDecimal();
            b=cin.nextBigDecimal();
            maxn=a.max(b);
            minn=a.min(b);
            k=(one.add(sqrt(five,105))).divide(two);
            res=(maxn.subtract(minn)).multiply(k);
            res=res.setScale(0,BigDecimal.ROUND_DOWN);
            if(res.compareTo(minn)==0)System.out.println(0);
            else System.out.println(1);
        }
    }
    public static BigDecimal sqrt(BigDecimal value, int scale){
        BigDecimal num2 = BigDecimal.valueOf(2);
        int precision = 100;
        MathContext mc = new MathContext(precision, RoundingMode.HALF_UP);
        BigDecimal deviation = value;
        int cnt = 0;
        while (cnt < precision) {
            deviation = (deviation.add(value.divide(deviation, mc))).divide(num2, mc);
            cnt++;
        }
        deviation = deviation.setScale(scale, BigDecimal.ROUND_HALF_UP);
        return deviation;
    }
}