题解 | #求解立方根#

import java.util.Scanner;
/**
二分查找法，不停的查找，知道差值< 0.000.1 即算为相等
这里只考虑非负数的情况，负数可以直接乘以-1得到
 */
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()) { // 注意 while 处理多个 case
            String s = in.nextLine();
            double num = Double.valueOf(s);
            boolean flag = true;
            if(num < 0){
                flag = false;
                num = -1 * num;
            }
            double result = 0;
            double i = 0;
            double j = num < 1 ? 1 : num;
            double mid = 0;
            while(i + 0.1 < j){
                mid = i + (j-i)/2;
                double temp = mid * mid * mid;
                if(temp < num){
                    i = mid;
                }else {
                    j = mid;
                }
            }
            
            if(num - i*i*i <= j*j*j - num){
                result = i;
            }else{
                result = j;
            }
            System.out.println(String.format("%.1f",(flag ? result : -1 * result)));
        }
    }
}