申論題

3. (20%) Write a pseudocode function that can re-construct a binary tree by using its preorder and inorder traversals. Please return the root of the binary tree as the output. Note: A node in a binary tree has two pointers, named 'lett' and 'right', respectively, where the 'left' pointer is used to find the left child of the node and the 'right' pointer is used to find the right child.