HDU 1194

给两数之和和两数之差，求两数，两数还必须同奇偶

#include <iostream>
using namespace std;
int main()
{
    int a,b,t;
    cin>>t;
    while(t--)
    {
        cin>>a>>b;
        int x = ( a + b ) / 2;
        int y = ( a - b ) / 2;
        if((a-b)%2||(a+b)%2||x<0||y<0) puts("impossible");
        else cout<<x<<" "<<y<<endl; 
    }
}