Strange fuction
Time Limit:1000MS Memory Limit:32768KB 64bit IO Format:%I64d & %I64uDescription
Now, here is a fuction:
F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100)
Can you find the minimum value when x is between 0 and 100.
F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100)
Can you find the minimum value when x is between 0 and 100.
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 only one real numbers Y.(0 < Y <1e10)
Output
Just the minimum value (accurate up to 4 decimal places),when x is between 0 and 100.
Sample Input
2
100
200
Sample Output
-74.4291
-178.8534
二分水题
#include <iostream> #include <cstdio> #include <math.h> #include <cstring> #include <algorithm> #include <iomanip> using namespace std; double y; double fx1(double x) { return 42*pow(x,6)+48*pow(x,5)+21*pow(x,2)+10*x-y; } //F(x) = 6 * x^7+8*x^6+7*x^3+5*x^2-y*x (0 <= x <=100) double fx(double x) { return 6*pow(x,7)+8*pow(x,6)+7*pow(x,3)+5*pow(x,2)-y*x; } int main() { //freopen("input.txt","r",stdin); int t; cin>>t; while(t--) { cin>>y; double l=0; double r=100; double mid; while(r-l>1e-8) { mid=(l+r)/2; if(fx1(mid)>0) { r=mid; } else { l=mid; } } cout<<fixed<<setprecision(4)<<fx(r)<<endl; } }