题目链接
思路:
满足条件的情况下只需要使得求出来的Lcm是最小的即可。
代码:
#include<bits/stdc++.h>
#define int long long
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int N=1e5+5;
const int M=2e4+5;
const double eps=1e-8;
const int mod=1e9+7;
const int inf=0x7fffffff;
const double pi=3.1415926;
using namespace std;
signed main()
{
IOS;
int t;
cin>>t;
while(t--)
{
int l,r;
cin>>l>>r;
if(l*2<=r)
{
cout<<l<<" "<<l*2<<endl;
}
else
{
cout<<-1<<" "<<-1<<endl;
}
}
return 0;
}