hdu 2199

Can you solve this equation?

Problem Description

Now,given the equation 8*x^4 + 7*x^3 + 2*x^2 + 3*x + 6 == Y,can you find its solution between 0 and 100;
Now please try your lucky.

Input

The first line of the input contains an integer T(1<=T<=100) which means the number of test cases. Then T lines follow, each line has a real number Y (fabs(Y) <= 1e10);

Output

For each test case, you should just output one real number(accurate up to 4 decimal places),which is the solution of the equation,or “No solution!”,if there is no solution for the equation between 0 and 100.

Sample Input

2 100 -4

Sample Output

1.6152 No solution!

#include <stdio.h>
long int y;
int a[6]={0,6,3,2,7,8};
int solve(double n)
{
    double x=1,sum=0;
    for(int i=1;i<=5;i++)
    { sum+=x*a[i];
      x*=n;}
     if(sum>y)
       return 1;
     else
       return 0;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t)
    {
            scanf("%ld",&y);
            double min=0,max=100,mid,ans;
            if(y>=6&&y<=807020306)
            {
               while(max-min>1e-8)
               {
                  mid=(min+max)/2;
                  if(solve(mid))
                    max=mid;
                  else
                    min=mid;

                }
               printf("%.4lf\n",max);
            }
             else
             printf("No solution!\n");
            t--;
    }
    return 0;
}

一道的简单的二分题，精度那里控制不好的会出现WA