Latest articles, tutorials, and deep dives from ndlab tech blog.
Every recursive solution is secretly a tree traversal. Once you see that, pruning becomes obvious. Master the backtracking template and 4 problem types found in every interview.
Sorting and binary search hide inside half your interview solutions. Master every sort variant, binary search on answer space, and the 3 patterns that turn O(n²) into O(n log n).
Graphs intimidate more than any other topic — but most problems use just 4 techniques. Master BFS, DFS, topological sort, and union-find with a clear decision framework.
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.
Stacks feel easy until the interviewer asks for a queue using two stacks. Learn the monotonic stack, deque patterns, and the BFS connection that unlocks hard O(n) solutions.
Linked lists look simple until live pressure hits. Master reversal, cycle detection, the runner technique, and merging — with the mental model that kills null pointer errors.
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