UESTC 1014 Shot

这题刚开始没想通，结果发现要解方程，代码如下：

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<algorithm>
#include<cstdlib>
#include<string>
#include<map>
#include<vector>
#include<set>
#include<numeric>
#define mod 1000000007
#define INT 2147483647
#define pi 3.141592654
//freopen("1.txt","r",stdin);
using namespace std;   

int main()
{
    double h,l,v;
    double alpha;
    double max=;  //yaojia h
    double height;
    while(scanf("%lf%lf%lf",&h,&l,&v))
    {
        if(h==&&l==&&v==)
            break;
        double kk=(v*v)/(9.8*l);
        double cita=atan(kk);
        double tt = l/(cos(cita)*v);
        double res = (v*sin(cita)*tt)-((9.8/)*tt*tt);
        printf("%.2f\n",res+h);
    }
    return ;
}