Typorithm learning path
Data Structures
Arrays & hashing, linked lists, stacks, queues, trees, heaps, tries, and graphs.
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Unit 1 · 7 topics
Arrays & Hashing
Hash maps and sets for lookups, counting, and grouping — the foundation of most problems.
Unit 2 · 8 topics
Linked Lists
Pointer manipulation — reversal, fast/slow pointers, dummy nodes, and cycle detection.
Reverse Linked List
easy · 9 activities
Middle of Linked List
easy · 9 activities
Merge Two Sorted Lists
easy · 9 activities
Linked List Cycle
easy · 9 activities
Remove Nth From End
medium · 9 activities
Reorder List
medium · 9 activities
LRU Cache
medium · 9 activities
Copy List with Random Pointer
medium · 9 activities
Unit 3 · 5 topics
Stacks & Queues
LIFO and FIFO with arrays — bracket matching, monotonic stacks, and queues from two stacks.
Unit 4 · 9 topics
Trees
Binary tree recursion — DFS depth, BFS levels, BST bounds, and lowest common ancestor.
Invert Binary Tree
easy · 9 activities
Maximum Depth
easy · 9 activities
Level Order Traversal
medium · 9 activities
Validate BST
medium · 9 activities
Lowest Common Ancestor (BST)
medium · 9 activities
Diameter of Binary Tree
medium · 9 activities
Binary Tree Traversals
easy · 9 activities
Serialize & Deserialize
hard · 9 activities
Balanced Binary Tree
medium · 9 activities
Unit 5 · 7 topics
Heaps
Array-backed binary heaps — sift up/down, top-K with a bounded heap, and linear heapify.
Unit 6 · 5 topics
Tries
Prefix trees with Map children — insert, word vs prefix search, wildcards, and shortest roots.
Unit 7 · 7 topics
Graphs
Grid and graph traversal — flood fill, multi-source BFS, cyclic clone, and dependency cycles.
Unit 8 · 6 topics
Union-Find
Disjoint sets with path compression and union by rank — components, cycles, and redundant edges.