Problem Description

Now, here is a fuction:
  F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100)
Can you find the minimum value when x is between 0 and 100.

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 only one real numbers Y.(0 < Y <1e10)

Output

Just the minimum value (accurate up to 4 decimal places),when x is between 0 and 100.

Sample Input

2
100
200

Sample Output

-74.4291
-178.8534

Author

Redow

#include <bits/stdc++.h>
using namespace std;

double po(double x,int y)
{
	double res=1;
	for(int i=0;i<y;i++)
		res*=x;
	return res;
}

int y;
double F(double x)
{  //函式先減後增
	return 6*po(x,7)+8*po(x,6)+7*po(x,3)+5*x*x-y*x;
}

int main()
{
	int T;
	scanf("%d",&T);

	while(T--)
	{
		scanf("%d",&y);

		double l=0,r=100;
		double res=-1;

		//三分
		for(int i=0;i<100;i++)
		{
			double lm=2.00*l/3.00+r/3.00;
			double rm=l/3.00+2.00*r/3.00;

			if(F(lm)<=F(rm))
			{
				res=lm;
				r=rm;
			}
			else
			{
				res=rm;
				l=lm;
			}
		}

		printf("%.4f\n",F(res));
	}
	return 0;
}