How should I practice Build a Tree from Preorder and Inorder Traversals?

Start by reading the full statement, solve the visible examples, then compare the pattern against related StackAdapt onsite interview problems in FastPrep.

Is Build a Tree from Preorder and Inorder Traversals associated with StackAdapt?

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Build a Tree from Preorder and Inorder Traversals

StackAdapt● MediumFULLTIMEONSITE INTERVIEW

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Problem statement

Reconstruct the unique binary tree described by the preorder and inorder traversals. All values are distinct.

Return the constructed tree in level order as strings. Use # for a missing child and remove all trailing # markers. Return an empty array for an empty tree.

Function

buildTreeLevelOrder(preorder: int[], inorder: int[]) → String[]

Examples

Example 1

preorder = [3,9,20,15,7]inorder = [9,3,15,20,7]return = ["3","9","20","#","#","15","7"]

The root is 3, with leaf 9 and a right subtree rooted at 20.

Example 2

preorder = []inorder = []return = []

Empty traversals construct an empty tree.

Constraints

0 <= preorder.length <= 10000.
Both arrays have equal length, contain the same distinct values, and describe a valid tree.