Please help me with this Breadth-first-Search problem. Please use c++

Sub-BST: Write a method/function that decides whether a given BST is a sub-BST of another BST. Note that a BST t_1 is a sub-BST of t_2 iff one of the following holds: a key[root[t_1]] = key[root[t2]]. and left[t_1] and right[t_1] are sub-BSTs of left [t_2] and right[t_2]. respectively. b. t_1 is a sub-BST of left[t_2] or c. t_1 is a sub-BST of right[t_2]