hdu 2199 Can you solve this equation?

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;
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

2100-4 

 

Sample Output

1.6152No solution!        

思路：二分

#include <iostream>#include <stdio.h>using namespace std;double pp=1e-7;int main(){    int t;    scanf("%d",&t);    while(t--)    {        int y;        scanf("%d",&y);        if(8*100*100*100*100+7*100*100*100+2*100*100+3*100+6<y || 6>y)        {            printf("No solution!\n");            continue;        }        double mid,low=0,high=100;        while(high-low>pp)        {            mid=(high+low)/2;            double s=8*mid*mid*mid*mid+7*mid*mid*mid+2*mid*mid+3*mid+6;            if(s>y)high=mid;            else low=mid;        }        printf("%.4f\n",high);    }}