UVALive 6428 A+B 扩展欧几里德

//参考博客http://blog.csdn.net/xmzyt1996/article/details/48865319

//题目:http://www.51isoft.com/v3/external/64/6428.pdf

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
typedef long long ll;
void ExtGcd(ll a,ll b,ll& d,ll& x,ll& y)
{
    if (b==0)
        d=a,x=1,y=0;
    else
    {
        ExtGcd(b,a%b,d,y,x);
        y-=x*(a/b);
    }
}
ll gcd(ll a,ll b)
{
    return b==0?a:gcd(b,a%b);
}
ll a, b, s, d, x, y;
int main()
{
    while (cin>>a>>b>>s)
    {
        if (a==0&&b==0)
        {
            cout<<(s==0?"YES":"NO")<continue;
        }
        if (a==0)
        {
            cout<<(s%b==0?"YES":"NO")<continue;
        }
        if (b==0)
        {
            cout<<(s%a==0?"YES":"NO")<continue;
        }
        ExtGcd(a,b,d,x,y);
        if (s%d!=0)
        {
            cout<<"NO"<continue;
        }
        a/=d,b/=d,s/=d;
        x*=s%b;
        x%=b;
        while (x<0)
            x+=b;
        y=(s-a*x)/b;
        while (y>=0)
        {
            if (gcd(x,y)==1)
            {
                cout<<"YES"<break;
            }
            x+=b,y-=a;
        }
        if (y<0)
            cout<<"NO"<return 0;
}