Meta Interview Question
How would you detect if a binary tree is a binary search tree?
Interview Answer
Anonymous
Nov 25, 2019
class Solution { public: bool isValidBST(TreeNode* root) { return isValidBST(root, LONG_MIN, LONG_MAX); } bool isValidBST(TreeNode* root, long mn, long mx) { if (!root) return true; if (root->val val >= mx) return false; return isValidBST(root->left, mn, root->val) && isValidBST(root->right, root->val, mx); } };