def Eval(path):
    output = "step3/out.txt" #输出结果的文件
    g=9.81
    #从文件中读取公式参数，检查有效性，并输出结果到文件
    #   请在此添加实现代码   #
    # ********** Begin *********#
    list2 = []
    with open(path,'r') as f1:
        list1 = f1.readlines()    
        v0 = float(list1[0].split(':')[-1])
        for i in range(2,len(list1)):
            for k in list1[i].split():
                list2.append(float(k))
        list2.sort()
        with open(output,'w')as f3:
            f3.seek(0)
            f3.truncate()
            f3.write('v0 = %.10f\n'%v0)
            f3.write('t\t\ty\n')
            for k in list2:
                if k<0 or k>2*v0/g:
                    f3.write('%.10f\tInvalid\n'%k)
                else:
                    y = v0*k - 1/2*g*k**2
                    f3.write('%.10f\t%.10f\n'%(k,y))