题解 | #求解立方根#

#include <cmath>
#include <iostream>
using namespace std;

int main(){
    double num;
    std::cin >> num;
    double val = num>0.0 ? num:-num;
    //std::cout << val << std::endl;
    double r = max(1.0,val),l=0.0,mid;
    //std::cout << r << std::endl;
    while(fabs(r-l) > 0.00001){
        mid = (r+l)/2;
        //std::cout << "r,l,mid:" <<r<<","<<l<<","<<mid<< std::endl;
        if(mid*mid<val/mid){
            l=mid;
        }else{
            r=mid;
        }        
    }
    if(num < 0) mid=-mid;
    printf("%.1f",mid);
    return 0;
}