题解 | #求解立方根#

import java.util.Scanner;
//二分查找
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNext()) {
            double num = in.nextDouble();
            System.out.println(binarySearch(num));
        }
    }


    public static double binarySearch(double num) {
        int isMinus = num<0?-1:1;
        num = Math.abs(num);
        double left = 0, right = num<1?1:num;
        while (right-left>0.1) {
            double med = (left + right) / 2;
            double x = Math.pow(med, 3);
            if (x == num) {
                return isMinus*(double)Math.round(med*10)/10;
            }
            else if(x>num){
                right = med;
            }
            else if(x<num){
                left = med;
            }
            //System.out.println(med);
        }
        double x1 = Math.pow(left, 3), x2=Math.pow(right, 3);
        if(Math.abs(x1-num) < Math.abs(x2-num)){
            return isMinus*(double) Math.round(left*10)/10;
        }
        else{
            return isMinus*(double) Math.round(right*10)/10;
        }
    }
}