题解 | #小红的取模构造#

#include <iostream>
using namespace std;

int main() {
    int t;
    cin >> t;
    while(t--){
        int a, b;
        cin >> a >> b;
        if(a == b && a == 0)cout << "1 1";
        else if(a == 0) cout << b * 2 << " " << b;
        else if(b == 0) cout << a << " " << a * 2;
        else if(a == b)cout << -1 << -1;
        else {
            if(a > b){
                cout << a << " " << a + b;
            }
            else cout << a + b << " " << b;
        }
        cout << endl;
    }
}
// 64 位输出请用 printf("%lld")

分类讨论