Can you solve this equation?
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 8846 Accepted Submission(s): 4075
Problem 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.
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
2 100 -4
Sample Output
1.6152 No solution!
Author
Redow
/*题解：
二分基础练习题
*/
#include<cstdio>
#include<cmath>
double fun(double x)
{
return 8*pow(x,4)+7*pow(x,3)+2*pow(x,2)+3*x+6;
}
int main()
{
int T;
double l,r,y,m,mid;
scanf("%d",&T);
while(T--)
{
scanf("%lf",&y);
if(fun(0)>y||fun(100)<y)
{
printf("No solution!\n");
continue;
}
l=0,r=100;
while(r-l>1e-7)
{
mid=(l+r)/2.0;
if(fun(mid)>y)
{
r=mid-1e-8;
}
else
{
l=mid+1e-8;
}
}
printf("%.4lf\n",(l+r)/2.0);
}
return 0;
}