Latest articles, tutorials, and deep dives from ndlab tech blog.
Trees are the most-tested structure in FAANG interviews. Master DFS, BFS, all traversals, LCA, path sums, and BST validation with a recursive framework that makes it click.
The hash map improves interview performance more than any other structure. Learn how it works, when O(1) breaks, and the 5 patterns covering 80% of hash-related problems.
Arrays and strings appear in 40%+ of interviews and hide surprising complexity. Master prefix sums, sliding windows, two pointers, and in-place tricks that turn O(n²) into O(n).
Every interview problem hides one of 14 patterns. Stop grinding LeetCode blind — recognize the right pattern in 30 seconds with trigger signals, templates, and a decision tree.
Big-O is the language interviewers speak. Get it wrong and you sound amateur — no matter how clever your solution. Build real intuition from O(1) to O(n!), plus a cheat sheet.
AI can write code. Copilot can solve LeetCode Mediums. So why do Google, Meta, and Amazon still put candidates through five rounds of algorithm interviews? The answer reveals something important about what companies are actually testing — and why understanding it changes how you prepare.
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