简单题
#include <cstdio> int main() { int t; scanf("%d", &t); while (t--) { int a, b, c, d; scanf("%d%d", &a, &b); c = (a + b) / 2; d = (a - b) / 2; if (a == c + d && b == c - d && c >= 0 && d >= 0) printf("%d %d\n", c, d); else printf("impossible\n"); } return 0; }