C

这题我用三分来做。

#include<iostream>#include<string.h>#include<string>#include<stack>#include<queue>#include<functional>#include<set>#include<map>#include<stdlib.h>#include<vector>#include<math.h>#include <algorithm>#pragma warning(disable:4996)using namespace std;double EPS = 1e-6;double find(double x,double y){return 6 * pow(x, 7) + 8 * pow(x, 6) + 7 * pow(x, 3) + 5 * pow(x, 2) - y*x;}double sf(double y){double lo=0, r=100,mid,mmid;while(r-lo>EPS){mid = (r + lo)/2;mmid = (mid + r)/2;if (find(mid,y) < find(mmid,y))r = mmid;elselo = mid;}return lo;}int main(){int t;scanf("%d", &t);while (t--){double y;scanf("%lf", &y);double d = sf(y);printf("%.4lf\n", find(d,y));}return 0;}