Leetcode Problem 98. Validate Binary Search Tree

98. Validate Binary Search Tree

Leetcode Solutions

Recursive Inorder Traversal

  1. Initialize a variable prev to store the value of the previously visited node during the traversal, initially set to None.
  2. Define a recursive function inorder that accepts a node and the prev variable.
  3. If the node is None, return True (base case for recursion).
  4. Recursively call inorder on the left child of the node.
  5. If prev is not None and the value of prev is greater than or equal to the current node's value, return False.
  6. Update prev to the current node's value.
  7. Recursively call inorder on the right child of the node.
  8. If all recursive calls return True, the tree is a valid BST.
UML Thumbnail

Recursive Traversal with Valid Range

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