Can you solve this equation?
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 6023 Accepted Submission(s): 2846
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
100
-4
Sample Output
1.6152
No solution!
No solution!
Author
Redow
一道初学者的二分题，讲课用
#include <iostream>
#include <cstdio>
using namespace std; double y; double getfx(double x){
return 8*x*x*x*x + 7*x*x*x + 2*x*x + 3*x + 6;
} void computing(){
if(getfx(100)<y-1e-3 || getfx(0)>y+1e-3){
printf("No solution!\n");
return;
}
double l=0,r=100;
while(r-l>1e-6){
double mid=(l+r)/2;
if(getfx(mid)>y) r=mid;
else l=mid;
}
printf("%.4lf\n",r);
} int main(){
int t;
scanf("%d",&t);
while(t-- >0){
scanf("%lf",&y);
computing();
}
return 0;
}