Strange fuction

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3209    Accepted Submission(s): 2348

2
100
200

-74.4291
-178.8534

代码如下：

<span style="font-size:14px;">#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#define eps 1e-6 
double cal(double x)
{
    return 42*pow(x,6)+48*pow(x,5)+21*pow(x,2)+10*pow(x,1);
}//自己设立求导函数 
double sum(double x,double y)
{
    return 6*pow(x,7)+8*pow(x,6)+7*pow(x,3)+5*pow(x,2)-x*y;
}
int main()
{
    int n;
    scanf("%d",&n);
    while(n--)
    {
        double low=0,high=100,y,mid;
        scanf("%lf",&y);
        while(high-low>eps)
        {//因为是double型所以比较的时候，要考虑精度的问题 
            mid=(high+low)/2;
            if(cal(mid)<y)//这是三分法，呵呵呵 导数小于零，继续因为是凹形 
            low=mid+1e-8;
            else
            high=mid-1e-8;
        }
        printf("%0.4lf\n",sum(mid,y));
    }
    return 0;
}</span>

该链接有关于二分法，三分法的一点小小的体会，不了解的可以去看看

http://blog.csdn.net/ice_alone/article/details/38420043

hdu 2899,布布扣,bubuko.com

hdu 2899

原文：http://blog.csdn.net/ice_alone/article/details/38420493