(Solved):
The red-black tree below remains valid if the color of nodes are changed. \( A, X \), and \( Y \) ...
The red-black tree below remains valid if the color of nodes are changed. \( A, X \), and \( Y \) \( \mathrm{Y}, \mathrm{C} \), and \( \mathrm{D} \) \( \mathrm{X}, \mathrm{P} \), and \( \mathrm{Q} \) \( \mathrm{P}, \mathrm{F} \), and \( \mathrm{G} \)