NPY and shot（三分）

#include<iostream>
#include<cstdio>
#include<string>
#include<cmath>
#include<queue>
#include<stack>
#include<map>
#include<cstring>
#include<algorithm>
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rev(i,a,b) for(int i=(a);i>=(b);i--)
#define clr(a,x) memset(a,x,sizeof a)
#define inf 0x3f3f3f3f
typedef long long LL;
using namespace std;

const double g=9.8;
const int maxn=2005;
const int maxm=4005;

double fun(double  h,double v,double x)
{
    double y=sqrt(1-x*x);
    return v*x*(v*y/g+sqrt((2*(h+v*v*y*y/2/g))/g));
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        double h,v;
        scanf("%lf%lf",&h,&v);
        double l =0,r =1;
        while(r-l>1e-8)
        {
            double mid1 = (l+r)/2;
            double mid2 = (mid1+r)/2;
            if(fun(h,v,mid1)>fun(h,v,mid2)) r = mid2;
            else l = mid1;
        }
        printf("%.2lf\n",fun(h,v,l));
    }
    return 0;
}