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;<br>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<br>100<br>-4<br>
   
   
   
   

 

Sample Output

   
   
   
   

    
    
    
    1.6152<br>No solution!<br>
   
   
   
   

简单题意：

  求出一个表达式的解；

解题思路形成过程：

  算法的优化是关键，采用二分法；

感想：

  这是一个简单的题目，并不需要太多的逻辑思维。

AC代码：

  #include <iostream>
#include <cmath>
#include <cstdio>
#include <algorithm>
double f(double x)
{
    return (8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6);
}
using namespace std;
int main()
{
    int t;
    cin>>t;
    for(int i=0;i<t;i++)
    {
        double y,mid;
        cin>>y;
        if(f(0)>y||f(100)<y)cout<<"No solution!"<<endl;
        else
        {
            double left=0,right=100;
            while(right-left>1e-10)
            {
                mid=(right+left)/2;
                if(f(mid)>y)
                    right=mid;
                else left=mid;
            }
            printf("%.4f\n",mid);
        }
    }
    return 0;
}