HJ107 求解立方根

https://www.nowcoder.com/practice/caf35ae421194a1090c22fe223357dca

强行二分，这是一种不好的解法，缝缝补补，又臭又长

import java.util.Scanner;
import java.math.BigDecimal;

public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int flag=0;
        String str=sc.nextLine();
        String[] split = str.split("\.");
        int prec=0;
        if (split.length==1)prec=0;
        else prec=split[1].length();
        double target=Double.valueOf(str);
        if(target<0){flag=-1;target=-target;}
        else flag=1;
        BigDecimal low=new BigDecimal("0.0");
        BigDecimal high=new BigDecimal(target);
        BigDecimal mid=new BigDecimal("0.0");
        if(target<=1)high=new BigDecimal(1.0);

        while (low.compareTo(high)<1){
            mid=(high.add(low)).divide(new BigDecimal("2.0")).setScale(2,BigDecimal.ROUND_DOWN);
            BigDecimal mid2=mid.multiply(mid.multiply(mid));
            double mid2Value=mid2.setScale(prec,BigDecimal.ROUND_HALF_UP).doubleValue();

            if (mid2Value==target){
                System.out.println(flag*(mid.setScale(1,BigDecimal.ROUND_HALF_UP).doubleValue()));
                return;
            }else if(mid2Value>target){
                high=mid.subtract(new BigDecimal("0.01"));
            }else{
                low=mid.add(new BigDecimal("0.01"));
            }


        }
        System.out.println(flag*mid.setScale(1,BigDecimal.ROUND_HALF_UP).doubleValue());
    }
}