hdu2199（高精度二分模版）

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.

#include<iostream>
#include<math.h>
#include<stdio.h>
using namespace std;
double deal(double x)
{
    return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        double x,sum,l=0,r=100;
        scanf("%lf",&sum);
        if(sum<deal(0)||sum>deal(100.0))
        {
            printf("No solution!\n");
            continue;
        }
        else
        {
            double mid;
            int flg=0;
            while(r-l>1e-6)
            {
                 mid=(l+r)/2;
                if(deal(mid)>sum)
                    r=mid;
                else
                    l=mid;
            }
            printf("%.4lf\n",r);
        }
    }
    return 0;
}