UVa 10812 - Beat the Spread!

#include <stdio.h>
#include <stdlib.h>

int main()
{
	int N,B,S;
	while ( scanf("%d",&N) != EOF ) 
	while ( N -- ) {
		scanf("%d%d",&B,&S);
		if ( B < S || (B+S)%2 ) 
			printf("impossible\n");
		else 
			printf("%d %d\n",(B+S)/2,(B-S)/2);
	}
	return 0;
}