Can you solve this equation? （二分搜索）解题报告

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.InputThe 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);OutputFor 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

2100-4

Sample Output

1.6152No solution!

#include <cstdio>#include <cmath>using namespace std;int main(){int t;scanf("%d",&t);while(t--){double y,l,r,mid;scanf("%lf",&y);l=0,r=100;if(y<6||y>807020306){printf("No solution!\n");continue;}while((r-l)>1e-8){mid=(l+r)/2;if(8*pow(mid,4)+7*pow(mid,3)+2*pow(mid,2)+3*mid+6==y)break;if(8*pow(mid,4)+7*pow(mid,3)+2*pow(mid,2)+3*mid+6>y){r=mid;}else if(8*pow(mid,4)+7*pow(mid,3)+2*pow(mid,2)+3*mid+6<y){l=mid;}}printf("%.4lf\n",mid);}return 0;}