Interview Patterns
Instead of memorizing 1000+ problems, master the 15 underlying patterns that solve 90% of interview questions.
Instead of memorizing 1000+ problems, master the 15 underlying patterns that solve 90% of interview questions. This hands-on tutorial focuses on practical implementation of interview patterns concepts.
Interview Patterns
The secret to cracking coding interviews isn't memorizing specific problems—it's recognizing identifying patterns. Most problems are just variations of a few core techniques.
1. Sliding Window
Used for arrays or linked lists to find a subrange that satisfies certain criteria.
- Identify: "Find the longest/shortest/max/min subarray/substring..."
2. Two Pointers
Two pointers moving in tandem or in opposite directions.
- Identify: "Find a pair/triplet in a sorted array..."
3. Fast & Slow Pointers (Tortoise & Hare)
Two pointers moving at different speeds.
- Identify: "Detect a cycle in a linked list/graph...", "Find the middle..."
4. Merge Intervals
Dealing with overlapping ranges.
- Identify: "Find intersections of intervals...", "Merge overlapping meetings..."
5. Top 'K' Elements
Using a Heap to keep track of the largest or smallest elements.
- Identify: "Find the Kth largest element...", "Shortest path to K points..."
Pattern Matrix
| Pattern | Data Structure | Time Complexity |
|---|---|---|
| Sliding Window | Array, Hash Map | O(n) |
| Modified Binary Search | Array (Sorted) | O(log n) |
| Topological Sort | Graph (DAG) | O(V+E) |
Strategic Advice
[!TIP] When you see a problem, first ask: "What is the brute-force way?" Then, ask: "What pattern can optimize this?" Usually, going from $O(n^2)$ to $O(n)$ involves a hash map, a heap, or a two-pointer window.
AI Mentor
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Quiz
Quiz
Question 1 of 1Which pattern is most effective for detecting a cycle in a linked list?