乘法逆元

以前的搬一下

#include<iostream>using namespace std;int p(int a,int b,int& x,int& y){    if(b==0){        x=1;        y=0;        return a;    }    int r=p(b,a%b,x,y);    int t=x;        x=y;        y=t-(a/b)*y;    return r;}int main(){    int n,m,x,y;    while(cin>>m>>n)    {p(m,n,x,y);    int k=(x%n+n)%n;    cout<<k<<endl;}    return 0;}