#include<iostream>
using namespace std;
int gcd(int a,int b)
{
return b ? gcd(a,a % b) : a;
}
int main()
{
int a,b;
cin >> a >> b;
cout << gcd(a,b) << endl;
return 0;
}
擴展歐幾里得算法
#include<cstring>
#include<algorithm>
#include<iostream>
using namespace std;
int exgcd(int a,int b,int &x,int &y)
{
if(!b) //邊界條件
{
x = 1, y = 0;
return a;
}
int d = exgcd(b,a % b,y,x);
y -= a / b * x;
return d;
}
int main()
{
int a,b,x,y;
cin >> a >> b;
int d = exgcd(a,b,x,y);
printf("%d * %d + %d * %d = %d",a,x,b,y,d);
return 0;
}