I'm job hunting and started practicing coding interview problems, but I'm struggling with questions that are labeled easy. During the last two years of college, I focused heavily on practical projects, especially backend MVC CRUD applications and ReactJS frontends. As a result, I haven't worked much with algorithms or data structures since earlier in college. Many problems seem vaguely familiar but still feel completely foreign. What concepts should I review first, and what free resources or study plans would help me rebuild my problem-solving skills from the ground up?
3 Answers
The gap you're feeling is normal. Building APIs and frontend applications uses different skills from reversing a binary tree or designing a dynamic-programming solution. A topic- or pattern-based list is more useful than grinding completely random questions. Work through ideas such as two pointers, sliding windows, binary search, stacks, breadth-first search, depth-first search, and eventually dynamic programming. Free tutorials and curated problem lists can help you learn one pattern, then practice several variations of it.
The main fix is consistent practice, but it helps to practice in a structured way rather than picking random problems. Start by reviewing arrays, strings, hash maps, linked lists, stacks, queues, recursion, sorting, and basic tree and graph concepts. Then solve a few problems from one topic at a time. After each problem, study the solution, understand the pattern, and try writing it again later without looking. The goal is to recognize common techniques, not to invent every solution from scratch.
Most people don't solve interview problems entirely from first principles under pressure. They recognize similarities to problems they've already studied. Try solving a problem for a reasonable amount of time, then read an explanation if you're stuck, understand why the approach works, and revisit it a few days later. Keep notes on the pattern and complexity. This builds a useful library of techniques much faster than repeatedly staring at problems you have no foundation for.
That makes sense. I haven't seriously studied data structures and algorithms since my sophomore year, so reviewing those fundamentals first is probably the right starting point.