hdu 2199 Can you solve this equation

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心情不好，简单的二分

#include<iostream>
#include<cstdio>
#include<cmath> 
using namespace std;
double y;
int cal(double x)
{
	return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
double find()
{
	double mid;
	double a,b;
	a=0;b=100;
	while(b-a>1e-8)
	{
		mid=(a+b)/2;
		if(cal(mid)<y) a=mid;
		else
		b=mid;
	}
	return (a+b)/2.0;
}
int main()
{
	int t;
	cin>>t;
	while(t--)
	{
		cin>>y;
		if(cal(0)<=y&&y<=cal(100)) printf("%.4f\n",find());
		else cout<<"No solution!"<<endl;
	}
	return 0;
}

hdu 2199 Can you solve this equation

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原文地址：http://blog.csdn.net/zafkiel_nightmare/article/details/44964279