题解 | #小红的取模构造#

# include<bits/stdc++.h>

using namespace std;

int t,a,b;
int main(){
    cin>>t;
    while(t--){
        cin>>a>>b;
        if(a==b && a!=0){
            cout<<-1<<" "<<-1<<endl;
            continue ;
        }
        if(a==b && a== 0){
            cout<<1<<" "<<1<<endl;
            continue;
        }
        if(a>b){
            if(a+b != a)
            cout<<a<<" "<<a+b<<endl;
            else
            cout<<a<<" "<<2*a+b<<endl;
            continue;
        }
        if(a<b){
            if(a+b != b)
            cout<<b+a<<" "<<b<<endl;
            else 
            cout<<2*b+a<<" "<<b<<endl;
            continue;
        }
    }


    return 0;
}

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