欧几里得算法与扩展欧几里得算法模板

#include<iostream>
#include<cstdio>
using namespace std;
int a,b,x,y;
int gcd(int a,int b)
{
    if(a%b==0)
    return b;
    return gcd(b,a%b);
}
int ex_gcd(int a,int b,int &x,int &y)
{
    if(b==0)
    {
        x=1;y=0;
        return a;
    }
    int r=ex_gcd(b,a%b,x,y);
    int t=x;x=y;y=t-a/b*y;
    return r;
}
int main()
{
    cin>>a>>b;
    cout<<gcd(a,b)<<endl;
    cout<<ex_gcd(a,b,x,y)<<endl;
    cout<<x;//x为a关于%b的乘法逆元
    return 0;
}