Can you solve this equation?--CSU-ACM2017暑假集训2-二分搜索

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!

double用printf输出时要用%f不是%lf,至少本地运行只能用%f

AC代码：

#include<iostream>#include<cstdio>using namespace std;const double preci=1e-8;double cal(double a){    return 8*a*a*a*a+7*a*a*a+2*a*a+3*a+6;}int main(){    int T;scanf("%d",&T);    while(T--)    {        double y;        scanf("%lf",&y);        if(y<cal(0)||y>cal(100))        {            printf("No solution!\n");            continue;        }        double left=0,right=100;        double mid;//        mid=(right+left)/2;//        cout<<mid<<endl;        while(right-left>1e-6)        {            mid=(right+left)/2;            if(cal(mid)>y)right=mid;            else left=mid;//            cout<<mid<<endl;        }        printf("%.4f\n",mid);    }}