Arrays
Array Operations in DSA (Java)
Learn how arrays work internally and master all core operations for interviews.
📌 Topics Covered
🚀 Basics of Arrays
Arrays store elements in contiguous memory locations and allow direct indexing.
💡 Key Insight: Array indexing starts from 0 and provides O(1) access.
Declaration
int[] arr = new int[5];
Characteristics
- Fixed size
- Contiguous memory
- Fast access
⚡ Array Operations
Access
Direct access using index → O(1)
Insertion
- Requires shifting elements
- Time complexity: O(n)
Deletion
- Shift elements left
- Time complexity: O(n)
Searching
- Linear Search → O(n)
- Binary Search → O(log n)
Sorting
- Quick Sort
- Merge Sort
- Bubble Sort
Merging Arrays
Used in divide & conquer and data processing.
📊 Complexity Analysis
- Access → O(1)
- Insertion → O(n)
- Deletion → O(n)
- Search → O(n) / O(log n)
✅ Best Practices
- Avoid index out of bounds
- Use efficient algorithms
- Optimize memory usage
💡 Always handle edge cases (empty array, single element).
🌍 Real-world Applications
- Databases
- Data processing
- Competitive programming
⚠️ Common Mistakes
- Index errors
- Wrong complexity assumptions
- Inefficient sorting
🎯 Conclusion
Array operations form the foundation of most algorithms and are essential for efficient programming.