扩展欧几里得

扩展欧几里得定理：对于两个不全为0的整数a、b，必存在一组解x,y，使得ax+by==gcd(a,b)

#include <bits/stdc++.h>using namespace  std;#define ll __int64 void exgcd( ll a, ll b, ll &x, ll &y)  {      if(b== 0)      {          x= 1;          y= 0;          return;      }      exgcd(b,a% b,x,y);      ll t= x;      x=y;      y=t-a/b*y;      return;  }  int main() {ll a, b, x, y;cin>>a>>b;exgcd(a, b, x, y);printf("%I64d %I64d\n", x, y);return 0;}