HDU 2199

#include <stdio.h>
#include <math.h>
double f(double x)
{
 return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
int main(int argc, char *argv[])
{
 int n;
 double y;
 double  l,r,m;
 scanf("%d",&n);
 while(n--)
 {
  scanf("%lf",&y);
  if(f(0)<=y&&f(100)>=y)
  {
    l=0;
    r=100;
    while(r-l>1e-6)	//高精度
    {
     m=(l+r)/2;
     if(f(m)>y)
      r=m;
     else if(f(m)<y)
      l=m;
    }
    printf("%.4lf\n",r);
  }
  else 
  printf("No solution!\n");
 }
 return 0;
}