10812-Beat The Spread!

#include<stdio.h>
int main()
{
    unsigned long s,d,t;
    //freopen("in.txt","r",stdin);
    scanf("%lu",&t);
    while(t--)
    {
        scanf("%lu%lu",&s,&d);
        if((s<d)||(s+d)&1)    //&1 use to check even or odd;s<d used for non negative & (s+d)&1 used for integer
            printf("impossible\n");
        else
            printf("%lu %lu\n",(s+d)>>1,(s-d)>>1); //(s+d)>>1=(s+d)/2,(s-d)>>1=(s-d)/2
    }
    return 0;
}