Arrays and strings are the most fundamental data structures in programming. Almost every problem in coding interviews starts with them.
An array is a collection of elements stored in contiguous memory. This allows fast access using indices. However, insertion and deletion can be costly.
Strings are essentially arrays of characters. Many problems involve string manipulation such as reversing, substring search, and pattern matching.
Key concepts:
- Indexing
- Traversal
- Sliding window technique
- Two pointer approach
Practice problems:
- Reverse array
- Two sum
- Longest substring without repeating characters
Mastering arrays and strings builds the foundation for advanced DSA topics.