Topic Mastery

Arrays

Foundation of all data structures. Sliding windows, two pointers, prefix sums — every interview starts here.

🔤

Strings

Pattern matching, anagrams, parsing. Strings appear in every real system from APIs to databases.

🗂️

Hash Maps

O(1) lookups, frequency counting, anagram detection. The most versatile tool in any coder's arsenal.

🔃

Sorting

Merge sort, quicksort, counting sort. Sorting problems appear deceptively simple but require deep insight.

📚

Stacks

LIFO structures powering expression evaluation, undo systems, DFS. Essential for 30+ interview patterns.

🔍

Binary Search

O(log n) search — find in sorted arrays, search rotated arrays, binary search on answers. A top interview topic.

🔗

Linked Lists

Pointer manipulation, reversal, cycle detection, merging. Classic interview problems loved by Google and Amazon.

🌳

Trees

Binary trees, BSTs, level order traversal. Backbone of file systems, databases, and 25%+ of all interview rounds.

🕸️

Advanced

Graphs

BFS, DFS, Dijkstra, topological sort. Master graphs to crack the hardest problems at tier-1 companies.

⚡

Advanced

Dynamic Programming

Memoization and tabulation for overlapping-subproblem optimization. The most feared — and most rewarding — topic.

🏗️

Advanced

System Design

Distributed systems, caching, load balancing, API design. The deciding factor for senior roles at FAANG.

⚙️

Backend

Rate limiters, auth flows, REST APIs, database design. Build real skills that translate directly to production work.