Complete courses — read, learn, bookmark.
From definition to Kadane's algorithm — every core array concept with Python, Java and C++ code.
From char operations to KMP — all the string tools you need for interviews.
Singly, doubly, circular lists with all standard operations and patterns.
LIFO / FIFO structures, monotonic stacks, deques and classic interview patterns.
Binary trees, BSTs, traversals, height, LCA, balancing — the full tree toolkit.
Representations, BFS, DFS, Dijkstra, topological sort, MST and union-find.
Memoization, tabulation and all the classic 1D/2D DP problems.
Bubble, Selection, Insertion, Merge, Quick, Heap, Counting — when and why to use each.
Search on sorted arrays and on answer space — patterns and pitfalls.
Base cases, recursive thinking, backtracking templates and the classic problems.
AND, OR, XOR, shifts, bitmasks and classic bit tricks.