[杂七杂八] Can you solve the equation?（二分求方程解）

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 <iostream>#include <cmath>#include <cstring>#include <cstdio>#include <algorithm>#include <iomanip>#define maxn 10000#define eps 10e-9using namespace std;double f(double x){    return 8*x*x*x*x + 7*x*x*x + 2*x*x + 3*x + 6;}int main(){    int t;    scanf("%d",&t);    double y;    while(t--)    {        scanf("%lf",&y);        double st=-1.0;        double end=101.0;        double mid;        while(end-st>eps)        {            mid=(end+st)/2;            if(f(mid)>=y)end=mid;            else st=mid;        }        if(mid<0||mid>100)//注意特判        {            printf("No solution!\n");        }        else printf("%.4f\n",mid);    }    return 0;}