The data structure behind many database and storage indexes
Validate Binary Search Tree
Ordered-tree validation, useful as nearby practice for index-style trees.
Insert into a Binary Search Tree
Practice ordered insertion logic and tree navigation.
Delete Node in a BST
Deletion cases mirror the kind of balancing logic tree indexes rely on.
Kth Smallest Element in a BST
Ordered traversal problem that connects well to indexed search structures.
Tree-shaped reasoning in compilers, compression, and decision systems
Binary Tree Level Order Traversal
Breadth-first traversal for layered hierarchical processing.
Maximum Depth of Binary Tree
Recursive depth aggregation over a hierarchical structure.
Lowest Common Ancestor of a Binary Tree
Tree-structured reasoning that combines results from subtrees.
Binary Tree Right Side View
Combines traversal order with visible-state reasoning.
Fast lookup for caches, symbol tables, and session state
Two Sum
The standard exact-key lookup problem for hash maps.
Valid Anagram
Frequency counting with a simple key-to-count map.
Group Anagrams
Canonical-key grouping built on hash table lookup.
Design HashMap
Closer to the data structure itself instead of just using a built-in map.
