Leetcode 2476. Closest Nodes Queries in a Binary Search Tree

For each query value, return the floor (largest value ≤ query) and ceil (smallest value ≥ query) that exist in the given binary search tree, using -1 when no such value exists. With up to 1e5 nodes/queries, solve efficiently by exploiting BST order (per-query traversal) or by inorder-sorting the tree and binary searching the array.