Consider the label sequences obtained by the following pairs of traversals on a labeled binary tree. Which of these pairs identify a tree uniquely?
- preorder and postorder
- inorder and postorder
- preorder and inorder
- level order and postorder
I've read that inorder is necessary to draw unique tree, well, I drawn the different tree with given options. I concluded that option $(2)$ and $(3)$ is true.
Can you explain formally please, why is tree not uniquely possible with given preorder and postorder traversal ?