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.
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);
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.
2 100 -4
1.6152 No solution!
這個題目唯一值得說的就是很明顯這個函數單增,端點值也很好求,直接判斷完之后二分就好,其它沒啥好說的了
#include <cmath>#include <iostream>using namespace std;double f(double x);int main(){ int t,y; double min,max,mid; cin>>t; while(t--){ cin>>y; if(y<6||y>=807020306){ cout<<"No solution!"<<endl; }else{ min=0; max=100; do{ mid=(min+max)/2; if(f(mid)>y){ max=mid; }else{ min=mid; } }while(fabs(f(mid)-y)>1e-6);新聞熱點
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