HUST 1541 解方程

参考自：https://www.cnblogs.com/ECJTUACM-873284962/p/6394836.html

1541 - Student’s question

时间限制：1秒 内存限制：128兆

题目描述

YY is a student. He is tired of calculating the quadratic equation. He wants you to help him to get the result of the quadratic equation. The quadratic equation’ format is as follows: ax^2+bx+c=0.

输入

The first line contains a single positive integer N, indicating the number of datasets. The next N lines are n datasets. Every line contains three integers indicating integer numbers a,b,c (a≠0).

输出

For every dataset you should output the result in a single line. If there are two same results, you should just output once. If there are two different results, you should output them separated by a space. Be sure the later is larger than the former. Output the result to 2 decimal places. If there is no solution, output “NO”.

输入　

3

1 2 1

1 2 3

1 -9 6

输出

-1.00

NO

0.73 8.27

解法：

 #include <bits/stdc++.h>
 using namespace std;
 int main()
 {
     double n,a,b,c;
     while(cin>>n)
     {
         while(n--)
         {
             cin>>a>>b>>c;
             if(a==)break;
             else
             {
             if(b*b-*a*c>=)
             {
                 double t1=(-b)/a;
                 double t2=c/a;
                 double t3=sqrt(t1*t1-*t2);
                 double x1=(t1+t3)/;
                 double x2=(t1-t3)/;
                 if(x1==x2) cout<<fixed<<setprecision()<<x1<<endl;
                 else if(x1<x2)
                 cout<<fixed<<setprecision()<<x1<<" "<<x2<<endl;
                 else if(x1>x2)
                     cout<<fixed<<setprecision()<<x2<<" "<<x1<<endl;
             }
             else cout<<"NO"<<endl;
             }
         }
     }
     return ;
 }