Coding interview problems, explained like a conversation.
Learn the pattern behind each problem, then practise how to talk through it: brute force first, then the optimal solution, then the follow-ups.
Learn the pattern, not the problem
Arrays & hashing
Constant-time lookups and counting duplicates.
Two pointers
Sorted input, pairs and in-place edits.
Sliding window
The longest or shortest range that meets a condition.
Stack
Matching brackets and next-greater-element problems.
Binary search
Sorted data and “smallest value that works” answers.
Trees & graphs
BFS, DFS and choosing the right traversal order.
Dynamic programming
Overlapping subproblems and optimal choices.
Heap
Top-k, merging streams and scheduling.
The same four steps, every time
Understand
Restate the problem, walk through examples and list edge cases.
Brute force
Start with the obvious solution and say why it is too slow.
Optimise
Spot the pattern and write clean code you can explain line by line.
Follow-ups
State time and space complexity, then handle the “what if…” questions.
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