POJ 2126

 1 #include <iostream>
 2 using namespace std;
 3 
 4 int n;
 5 
 6 int main()
 7 {
 8     //freopen("acm.acm","r",stdin);
 9     cin>>n;
10     int a;
11     int b;
12     int c;
13     int i;
14 
15     if(n < 2)
16     {
17         cout<<"YES"<<endl;
18         for(i = 0; i < n; ++ i)
19         {
20             cin>>a;
21         }
22     }
23     else if(n > 2)
24     {
25         cout<<"NO"<<endl;
26         for(i = 0; i < n; ++ i)
27         {
28             cin>>a;
29         }
30     }
31     else 
32     {
33         cin>>a>>b>>c;
34         if(b * b - 4 * a * c < 0)
35         {
36             cout<<"YES"<<endl;
37         }
38         else 
39         {
40             cout<<"NO"<<endl;
41         }
42     }
43 }