BST
Detailed guide and Python implementation for the 'BST' problem.
Problem Statement
Write a function is_valid_bst(tree_arr) that takes an array representation of a binary tree tree_arr (root at index 0, children of i at 2i+1 and 2i+2, with None representing empty nodes) and returns True if it is a valid Binary Search Tree (BST), or False otherwise.
- •0 <= len(tree_arr) <= 1000
Examples
tree_arr = [2, 1, 3]
True
The left child 1 is smaller than root 2, and right child 3 is greater than root 2.
tree_arr = [5, 1, 4, None, None, 3, 6]
False
The root value is 5, but its right child 4 contains a left child 3 which is smaller than 5.
Need a Hint?
Edge Cases to Watch
- Empty input structures
- Single element inputs
- Large numerical bounds
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