Can you solve this equation?（二分）

Can you solve this equation?

Time Limit : 2000/1000ms (Java/Other)   Memory Limit : 32768/32768K (Java/Other)

Total Submission(s) : 61   Accepted Submission(s) : 37

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.

 

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!

 

题解：二分法

代码：

 #include<stdio.h>
 double abs(double x){
     return x>?x:-x;
 }
 double operate(double x){
     return  *x*x*x*x+*x*x*x+*x*x+*x+6.0;
 }
 double search(double y){
     double l=,r=,mid;
     while(r-l>1e-){mid=(l+r)/;
         if(operate(mid)<y)l=mid;
         else r=mid;
         if(abs(operate(mid)-y)<1e-)break;
     }
     return mid;
 }
 int main(){
     int T;
     double Y;
     scanf("%d",&T);
     while(T--){
         scanf("%lf",&Y);
         if(Y<operate()||Y>operate())puts("No solution!");
         else printf("%.4lf\n",search(Y));
     }
     return ;
 }