其實(shí)就是實(shí)系數(shù)多項(xiàng)式分解定理!n>=1的實(shí)系數(shù)多項(xiàng)式在實(shí)數(shù)域上都可以分解成一次因式與二次不可約因式的乘積!
在實(shí)數(shù)域上，奇次一定有一個(gè)根，偶次有共軛虛根,總是可以分解成兩個(gè)n/2的多項(xiàng)式。

#include <iostream>
#include <iomanip>
using namespace std;

int main()
{
    int a,b,c,n;
    while(cin>>n)
    {
        if(n<2)    
        {
            while(n>=0)
            {
                n--;
                cin>>a;
            }
            cout<<"YES"<<endl;
        }
        else if(n==2)
        {
            cin>>a>>b>>c;
            if(b*b>=4*a*c)
                cout<<"NO"<<endl;
            else
                cout<<"YES"<<endl;
        }
        else
        {
            while(n>=0)
            {
                n--;
                cin>>a;
            }
            cout<<"NO"<<endl;
        }
    }
    return 0;
}