codevs 1200NOIP 2012同余方程 拓展欧几里德求乘法逆元模板题

Posted 2020-06-22 abclzr

模板，，，

#include<cstdio>
using namespace std;
void exgcd(long long a,long long b,long long &x,long long &y){
	if (b==0) {x=1; y=0;}
	else {exgcd(b,a%b,x,y); int t=y; y=x-a/b*y; x=t;}
}
int main(){
	long long a,b,x,y;
	scanf("%lld %lld\n",&a,&b);
	exgcd(a,b,x,y);
	printf("%lld\n",(x+b)%b);
	return 0;
}