This DSA interview sheet is designed as a fast revision layer over the full DSA Course: Interview Patterns and Problem Solving. Use it to decide which pattern fits a problem, then open the linked lesson for brute force, optimized approach, pseudocode, Python, C++, Java, and quiz practice.
High-Value Pattern Map
| Topic | Core Pattern | Practice Link |
|---|---|---|
| Arrays | Hash map, Kadane, two pointers | Two Sum |
| Hashing | Frequency map, prefix sum | Subarray Sum Equals K |
| Trees | DFS recursion, BFS queue | Level Order Traversal |
| Graphs | DFS/BFS, topological sort, union find | Number of Islands |
| DP | State transition, pick/skip, 2D table | Coin Change |
How To Use This Sheet
- Read the prompt and identify the data movement: scan, lookup, boundary, recursion, graph walk, or state transition.
- Say the brute force first so the optimized approach has context.
- Write exact pseudocode before full code.
- Do one dry run with state changes, not only final output.
- End with time and space complexity.
Quick Diagram
Prompt -> Brute Force -> Repeated Work -> Pattern -> Pseudocode -> Code -> Dry Run -> QuizFAQs
Should I solve problems topic-wise or pattern-wise?
Start topic-wise for fundamentals, then revise pattern-wise before interviews.
How many DSA questions are enough?
A focused set of 75 to 100 questions is enough if every solution includes reasoning, dry run, and complexity.