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New content

10 new coding challenges

Ten new multi-level coding challenges - Basic Calculator, LRU Cache, Merge Intervals Family, Lowest Common Ancestor Family, Binary Tree Vertical Order, Valid Palindrome With Deletions, Weighted Random Pick, Nested List Weights, Kth Largest Element, and Dasher Payout Engine.

Released1mo ago
New content

17 new DSA practice questions

Seventeen new LeetCode-style practice questions across the DSA core concepts - arrays, binary search, bit manipulation, DFS, dynamic programming, graphs, greedy, hash maps, queues, recursion, sorting, trees, and union find - each with labeled examples, constraints, and a Solution Breakdown.

Released1mo ago
Update

DSA pages aligned - canonical examples and Solution Breakdown

Every DSA core concept page now follows one structure - standalone canonical example pages, LeetCode-style problem formatting with labeled examples and constraints, a renamed Solution Breakdown section, and difficulty-ordered question sets.

Released1mo ago
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6 of 53 questions
Companies
  • Stack Samples → Trace Events

    A sampling profiler captures call stacks at fixed intervals. Convert those snapshots into start/end span events. Three phases - basic diff, recursion, then a min-consecutive-count debounce.

    Coding
    hard
    Anthropic
    5mo
  • In-Memory Key-Value Store

    Build a key-value store as a single class. Layer on prefix-scan, TTL, then gzip persistence - each phase is its own surface area on top of the previous one.

    Coding
    medium
    OpenAI
    5mo
  • Encode and Decode Strings

    Serialize a list of arbitrary strings into a single string and parse it back. Any character is allowed in the strings, including the delimiters - the format must round-trip them all.

    Coding
    easy
    GoogleBloomberg
    5mo
  • Time-Based Key-Value Store

    A key-value store with timestamped writes. Read at time t returns the latest value written at or before t; later phases add arbitrary-order inserts and range queries.

    Coding
    medium
    OpenAIGoogle
    5mo
  • Unix cd with Symlink Resolution

    A stateful shell that supports POSIX cd semantics - absolute and relative paths, `.`/`..`, symlink resolution, and cycle detection.

    Coding
    medium
    OpenAIMetaAnthropic
    5mo
  • Valid Parentheses

    Five escalating takes on one bracket string: validate it, point editor squigglies at it, mine the longest valid substring, repair a broken file, and validate with a corruptable wildcard.

    Coding
    hard
    GoogleBloomberg
    5mo