Arrays and Strings Interview Questions | Data-Structures | NextRound

1What is the Two-Pointer technique? Give a use case.Beginner

2Why are Strings immutable in Java/C#? What are the benefits?Intermediate

3What is a Dynamic Array (ArrayList/Vector)? How does it grow?Intermediate

4Why is string concatenation in a loop O(n²)? How do you fix it? (StringBuilder)Intermediate

5Explain the concept of Amortized O(1) for Dynamic Array insertion.Intermediate

6Explain Kadane's Algorithm (Maximum Subarray Sum). What is its complexity?Intermediate

7How do you rotate an array by k positions? (In-place vs extra space)Beginner

8What is the difference between a String and a Character Array?Intermediate

9Why is accessing an array element O(1)?Beginner

10How do you check if two strings are anagrams of each other?Beginner

11Explain how to find the longest palindromic substring.Intermediate

12Why is insertion/deletion in the middle of an array O(n)?Beginner

13What is an Array? How is it stored in memory?Beginner

14What is the Sliding Window technique? Give a use case.Intermediate

15What are the advantages and disadvantages of Arrays?Intermediate

16What is String Interning?Intermediate

17How do you find the second largest element in an unsorted array?Beginner

18What is a Sparse Array? When is it useful?Intermediate

19What is the Prefix Sum technique?Intermediate