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：
1 #include <bits/stdc++.h> 2 using namespace std; 3 int main() 4 { 5 double n,a,b,c; 6 while(cin>>n) 7 { 8 while(n--) 9 { 10 cin>>a>>b>>c; 11 if(a==0)break; 12 else 13 { 14 if(b*b-4*a*c>=0) 15 { 16 double t1=(-b)/a; 17 double t2=c/a; 18 double t3=sqrt(t1*t1-4*t2); 19 double x1=(t1+t3)/2; 20 double x2=(t1-t3)/2; 21 if(x1==x2) cout<<fixed<<setprecision(2)<<x1<<endl; 22 else if(x1<x2) 23 cout<<fixed<<setprecision(2)<<x1<<" "<<x2<<endl; 24 else if(x1>x2) 25 cout<<fixed<<setprecision(2)<<x2<<" "<<x1<<endl; 26 } 27 else cout<<"NO"<<endl; 28 } 29 } 30 } 31 return 0; 32 }