Blog

Stop casting with `as` and `!`. Discriminated unions give TypeScript enough information to narrow types automatically — making impossible states unrepresentable and exhaustiveness checking free.

Jump Game, Gas Station, and Partition Labels — three greedy DSA patterns that feel like guesswork until you see the invariant that makes each one provably correct.

Three 1D DP patterns that show up in every senior interview: LIS, Max Product Subarray, and Word Break — with brute force, optimized, and Trie-based solutions in JavaScript.

Grid navigation, sequence alignment, and string transformation — three canonical 2D DSA DP patterns explained with JavaScript, tables, and interview-ready solutions.

DP doesn't have to be scary. Learn the framework — define state, write recurrence, nail base cases — through Climbing Stairs, House Robber, and Coin Change.

Grid problems are graph problems in disguise. Learn the DFS/BFS traversal pattern that unlocks Number of Islands, Clone Graph, and Pacific Atlantic Water Flow.

Topological sort is how you order things with dependencies. Learn the DFS three-state and Kahn's BFS approaches to ace Course Schedule, Course Schedule II, and Alien Dictionary.

Multi-source BFS is single-source BFS with all starting points seeded at once. Master this pattern and you can solve Rotting Oranges, Walls and Gates, and Word Ladder in one mental model.

Backtracking is just DFS with an undo step. Master the three templates for subsets, permutations, and combinations — and the one mistake that ruins every solution.