Problem Description
Now, here is a fuction:<br> F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100)<br>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<br>100<br>200
Sample Output
-74.4291<br>-178.8534
題意：求F(x)最小值
思路：求導就行了，注意精度
感想：二分三分都行，那個y唬人的，沒什麼用
AC代碼：
#include <cstdio>
#include<iostream>
#include<stdio.h>
#include<vector>
#include<algorithm>
#include<numeric>
#include<math.h>
#include<string.h>
#include<map>
#include<set>
#include<vector>
#include<iomanip>
using namespace std;
double y;
double q1(double x)
{
return 6*x*x*x*x*x*x*x+8*x*x*x*x*x*x+7*x*x*x+5*x*x-y*x;
}
double q (double x)
{
return 42*x*x*x*x*x*x+48*x*x*x*x*x+21*x*x+10*x-y;
}
int main()
{
double x,h,l,mid;
int N;
cin>>N;
while(N--)
{
cin>>y;
l=0;
h=100;
while((h-l)>0.000000001)
{
mid=(h+l)/2;
if(q(mid)>0) h=mid;
else l=mid;
}
mid=q1(mid);
printf("%.4f\n",mid);
}
}
