Given the root of a binary tree, determine if it is a valid binary search tree (BST). A valid BST has these properties: - The left subtree of a node contains only nodes with keys less than the node's key - The right subtree contains only nodes with keys greater than the node's key - Both left and right subtrees must also be valid BSTs Example: [, , ] is valid. [, , , null, null, , ] is not (the is in the right subtree of but < ).
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$ curl repovive.com/roadmaps/maang-interview-prep/trees-bst/problem-validate-binary-search-tree
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