扩展欧几里得

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

int exgcd(int a,int b,int &x,int &y){
if(!b){
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;
}