二分查找法
#include <algorithm>
#include <cmath>
#include <iomanip>
using namespace std;
int main() {
double x;
while(cin>>x){
double out;
double left,right;
if(x>=0&&x<1) {
left = x;
right = 1.0;
}
else if(x<0&&(x>-1)){
right = x;
left = -1.0;
}
else if (x>=1){
left = 1.0;
right = x;
}
else if (x<=1){
left = x;
right = -1.0;
}
while((right-left)>0.01){
out = (right+left)/2;
if(out*out*out>x) right =out;
else left = out;
}
cout<<fixed<<setprecision(1)<<out<<endl;
}
}