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Lessons (17)

• System Design Interview Framework

  A seven-step path from an ambiguous prompt to a clear, trade-off-aware architecture discussion. ![Interview flow …

• SQL Interview Query Drills

  … define grouping, compute an aggregate, then filter with a clear tie policy](/img/database-interviews/sql-drills.svg …

• DSA Interview Patterns Cheat Sheet

  Map any coding-interview problem to the right technique in seconds. Keyword triggers, a decision flowchart, complexity tables …

• DBMS Foundations, Keys & Normalization

  Detailed interview answers for DBMS advantages, normalization, keys, abstraction and conceptual design. Covers PDF questions 1-5, 12 …

• Views, Triggers & Stored Procedures

  … Transaction-control and return-value capabilities vary by engine, so name the product in an interview.

• Transactions, Indexes & Concurrency

  … transactions protect invariants while indexes speed access and locks coordinate writers](/img/database-interviews/transactions.svg) Q8: What …

• SQL Language, Identifiers & Data Types

  Interview answers for DDL/DML/DCL, generated IDs, UNION, static/dynamic SQL and CHAR/VARCHAR. Covers PDF questions …

• Hash Maps & Sets

  The interview superpower. Learn how hashing gives O(1) lookups, how collisions are handled, and the patterns (counting …

• Arrays & Strings

  … Sorting both strings and comparing works too, but costs O(n log n). Common interview gotchas - Off-by …

• ACID, Transactions & Locks

  … In an interview, name the isolation level and the anomaly you are preventing instead of saying “use transactions …

• Stacks & Queues

  … Two simple structures behind undo buttons, browser history, task scheduling and many interview problems. The big idea ![A …

• Linked Lists

  … Reverse a linked list ⭐ The 1 linked-list interview question. Use three pointers: prev , current , next . js function …

• Two Pointers & Sliding Window

  … Learn them with animated-style diagrams and classic interview examples. Two Pointers The big idea Two people searching …

• Trees & Binary Search Trees

  … disk pages even with millions of rows. Classic interview problems js // Is this a valid BST? Every node …

• Heaps & Priority Queues

  … so this is worth knowing by heart for interviews: js class MinHeap { items = []; compare; constructor(compare = (a, b …

• Graphs: BFS & DFS

  … every node and edge is handled once. Grids are graphs too ⭐ Many interview problems hide a graph inside …

• Normalization & Denormalization

  … Metric for stale/failed projections. Interview-ready answer I normalize to ensure one fact has one authoritative home …