SDE - 1

Tip 1: Practice classic stack problems (Balanced Parentheses, Next Greater Element, Stock Span, etc.).
Tip 2: Learn common patterns like Monotonic Stack, Backtracking with Stack, Expression Evaluation.
Tip 3: Always do a step-by-step dry run to understand stack push-pop behaviour clearly.

Tip 1: Practice key greedy algorithm problems (like Activity Selection, Fractional Knapsack) to understand common patterns.
Tip 2: Identify if the problem has the greedy-choice property and optimal substructure before attempting a greedy solution.
Tip 3: Compare with dynamic programming approach when in doubt - greedy works only if local decisions are always globally optimal.

Tip 1: Start with recursion followed by memorization and finally tabulation for a solid understanding.
Tip 2: Learn common DP patterns (0/1 Knapsack, Longest Increasing Subsequence, Matrix Chain Multiplication, etc.).
Tip 3: Practice breaking problems into overlapping subproblems and state definitions to design your DP solution effectively.

Tip 1: Learn key algorithms like KMP, Rabin-Karp, Z Algorithm, and Naïve Approach.
Tip 2: Learn to identify string matching patterns (exact match, substring search, pattern with wildcards).
Tip 3: Practice problems involving substring search, pattern matching, and string pre-processing techniques.

Tip 1: Focus on OOP principles and how they apply in real-world scenarios.
Tip 2: Implement small programs using Streams, exceptions, and custom logic to strengthen understanding.
Tip 3: Basics of garbage collection, memory management, and object lifecycle to handle conceptual questions confidently.

Tip 1: Understand core thread concepts i.e. Threads, synchronization, race conditions, and critical sections.
Tip 2: Implement Producer-Consumer, Reader-Writer, and other concurrency patterns to understand coordination.
Tip 3: Know thread control methods like wait() , notify(), notifyAll(), sleep() and yield().

Tip 1: Learn the purpose and correct usage of common Spring annotations and how they affect dependency injection and bean management.
Tip 2: Explore annotations like @Cacheable, @CacheEvict, and @CachePut and understand how caching improves application performance.
Tip 3: Build small Spring Boot projects to apply annotations and caching practically, reinforcing understanding for interviews.

Tip 1: Practice GROUP BY with aggregation functions.
Tip 2: Use HAVING to filter grouped results.
Tip 3: Practice Query Optimization.