Technology & Software

Practice covering WebSockets persistent full-duplex TCP RFC 6455, localStorage vs sessionStorage, Service Workers PWA offline caching proxy, Sass/SCSS preprocessors, JavaScript 'use strict' mode, Functional Currying f(a)(b)(c), Shadow DOM encapsulation in Web Components, Segment Trees range queries O(log N), Fenwick Trees (Binary Indexed Tree) prefix sums, Knuth-Morris-Pratt (KMP) string matching O(N+M) with LPS array, and NP-Completeness (Cook's Theorem, 3-SAT, Polynomial verification in NP).

Practice covering RESTful API idempotency (POST non-idempotent), CORS Preflight OPTIONS requests, CSS 1D Flexbox vs 2D Grid, DOM Event Capturing vs Bubbling, Promise.all() concurrency, V8 JIT compilation (TurboFan / Ignition), Backtracking pruning, Huffman Coding greedy min-heap prefix codes, Trie (Prefix Tree) O(L) dictionary lookup, Bitwise trick x & (x - 1) clearing lowest set bit, Disjoint Set Union by Rank & Path Compression with Inverse Ackermann alpha(N), and C++ Smart Pointers (unique_ptr vs shared_ptr reference counting).

Practice covering BFS Queue vs DFS Stack, Dijkstra greedy failure on negative weights, Bellman-Ford O(V*E) negative cycle detection, Floyd-Warshall O(V^3) All-Pairs DP, Kruskal's MST Greedy with Disjoint Set Union (DSU Union-Find O(E log E)), Topological Sort DAG Kahn's in-degree algorithm, Fractional Knapsack Greedy vs 0/1 Knapsack Dynamic Programming, DP Optimal Substructure & Overlapping Subproblems, Longest Common Subsequence (LCS) O(MN) DP matrix, JavaScript Event Loop (Microtask Queue Promises priority over Macrotask Queue setTimeout), Closures & Lexical Scopes, and Prototypal Inheritance & Prototype Chain delegation.

Practice covering Merge Sort O(N) auxiliary space vs Quick Sort in-place partitioning, Quick Sort O(N^2) worst case on sorted arrays, Binary Heap array indexing (Left: 2i+1, Right: 2i+2, Parent: (i-1)/2), Floyd's Build-Heap linear O(N) proof, Comparison sort Omega(N log N) decision tree lower bound, Inorder BST sorted traversal, AVL Tree Balance Factor {-1,0,+1} & Rotations, Red-Black Trees (Color properties, black-height, C++ std::map), BST deletion (Inorder Successor/Predecessor), and Graph space (Adjacency Matrix O(V^2) vs List O(V+E)).

Practice covering CSS Specificity hierarchy, HTTP status codes (200, 404, 500), JavaScript Variable Hoisting, C Header Guards (#ifndef), typedef, strncpy() buffer overflow defense, Bitwise XOR cancellation (x ^ x = 0), Bitwise shift multiplication/division (x << 1, x >> 1), Java Generational Garbage Collection, Array O(1) vs Linked List O(K) access, Formal Asymptotic Notations (Big-O upper bound, Big-Theta tight bound), and Master Theorem calculations (Merge Sort T(n)=2T(n/2)+n -> Theta(n log n), Case 1/2/3).

Practice covering Circular Queue modulo pointer arithmetic (rear+1)%N, Deque, Doubly Linked List bidirectional pointers, Floyd's Cycle Detection (Tortoise and Hare), Insertion Sort O(N) best case, Selection Sort O(N) minimal swaps, Sorting Stability, CSS Box Model (Content, Padding, Border, Margin), box-sizing: border-box, CSS Flexbox justify-content main axis, DOM addEventListener(), document.querySelector(), JS loose (==) vs strict (===) equality, Arrow functions lexical this, and JSON.stringify() vs JSON.parse().

Practice covering Call by Value vs Call by Reference, Recursion base case, C++ Copy Constructor (deep copy), Diamond Problem & Virtual Base Classes, Function Overloading vs Method Overriding, C++ Virtual Functions & vtable/vptr mechanics, Pure Virtual Functions & Abstract Classes, Access Specifiers (public, private, protected), Java Interface multiple implementation, Java final keyword, Python list comprehensions & __init__(self), 2D Array Row-Major memory math B + (i*N + j)*W, Infix to Postfix conversion, and Postfix stack evaluation math.

Practice covering CSS acronym, ID (#) vs Class (.) selectors, external <link>, JavaScript console.log(), alert(), let vs const, HTML semantic tags (<header>/<nav>/<article>/<section>/<footer>), <table>/<tr>/<td>, HTML comments, C pointer mechanics (scaling by sizeof(type)), Special Pointers (Dangling, Void), Dynamic Memory Allocation (malloc vs calloc zero-init, memory leaks), Storage Classes (auto, static persistence, extern cross-file), Structures vs. Unions (shared memory for largest member), Structure padding & 4-byte alignment, and Array-pointer equivalence (*(arr+i)).

Practice covering Classes vs Objects, Linear vs Non-Linear data structures, Stack LIFO & Overflow/Underflow, Queue FIFO, 0-based array indexing & contiguous memory layout, Singly Linked List nodes (Data/Next/NULL), Tree terminology (Root, Leaf), Binary Trees (at most 2 children), BST ordering property, Linear Search O(N) vs Binary Search sorted prerequisite, Python immutability (Tuples), HTML5 DOCTYPE declaration, tags (<a> href, <img> src/alt, <ol>/<ul> lists, <h1>-<h6>).

Practice covering Compilers vs Interpreters, C history (Dennis Ritchie), 32 C keywords, identifier rules, escape sequences, increment operators (++x vs x++), sizeof compile-time operator, ternary operator, do-while vs while loop mechanics, switch fallthrough, break vs continue, language creators (Bjarne Stroustrup, James Gosling, Guido van Rossum, Brendan Eich), and 4 Pillars of OOP (Encapsulation, Abstraction, Inheritance, Polymorphism).

Practice covering Comprehensive Advanced DBMS Architecture, Distributed Database Sharding, Relational Calculus, Concurrency Control Protocols, Normalization Theory Mastery, and Query Optimization Engineering.

Practice covering Timestamp Ordering & Thomas' Write Rule obsolete write handling, Multi-Version Concurrency Control (MVCC snapshot isolation), OLTP normalized 3NF vs OLAP denormalized Star/Snowflake schemas, Fact vs Dimension tables, Columnar analytical storage efficiency, Database Join Algorithms (Hash Join build-probe vs Sort-Merge Join linear scan), NTILE quartile partitioning, Tuple Relational Calculus (TRC) vs Domain Relational Calculus (DRC), Second-Order SQL Injection, Recursive CTEs, and Heuristic Relational Algebra Predicate Pushdown (Push Down Selections).