checking subtrees using preorder and inorder strings

Question

A book I\'m reading claims that one way to check whether a binary tree B is a subtree of a binary tree A is to build the inorder and <

Answer 1

As supplement to user1952500's answer: if it is a binary search tree, either only preorder or only postorder can make it unique, while only inorder can not. For example:

  5
 / \
3   6

inorder: 3-5-6 however, another binary search tree can have the same inorder:

3
 \
  5
   \
    6

Also, I believe preorder+inorder+string_comparison only works to check whether two trees are identical. It fails to check whether a tree is the subtree of another tree. To see an example, refer Determine if a binary tree is subtree of another binary tree using pre-order and in-order strings