公式 p+q-gcd(p,q)就是所求值

 

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
int gcd(int n,int m)
{
  if(m==0)
  return n;
  gcd(m,n%m);
}
int main()
{
  int m,n;
  while(cin>>m>>n)
  {
    cout<<m+n-gcd(m,n)<<endl;
  }
}

The article write by nealgavin