不需要考虑边界所以比较简单 题目790

#include <iostream>

using namespace std;

int main()
{
    double x;
    cin >> x;

    double l = -100, r = 100;
    while (r - l > 1e-8)//保留4位小数1e-6，5位小数1e-7,6位小数1e-8
    {
        double mid = (l + r) / 2;
        if (mid * mid * mid >= x) r = mid;
        else l = mid;
    }

    printf("%.6lf\n", l);

    return 0;
}