What type of coding questions will be asked in an interview?

In a coding interview, you can expect a variety of questions that test your understanding of data structures, algorithms, problem-solving skills, and sometimes your ability to design scalable systems. Here are the common types of coding questions typically asked:

1. Data Structures and Algorithms

Arrays and Strings:

• Find the largest/smallest element in an array.
• Reverse a string or array.
• Check if a string is a palindrome.
• Implement an algorithm to rotate an array.

Linked Lists:

• Reverse a linked list.
• Detect a cycle in a linked list.
• Merge two sorted linked lists.
• Remove the nth node from the end of a linked list.

Stacks and Queues:

• Implement a stack using an array or linked list.
• Implement a queue using two stacks.
• Evaluate a postfix expression.
• Check for balanced parentheses in an expression.

Trees and Graphs:

• Traverse a binary tree (in-order, pre-order, post-order).
• Implement a binary search tree (BST) and perform operations (insert, delete, find).
• Find the lowest common ancestor (LCA) of two nodes in a BST.
• Perform breadth-first search (BFS) and depth-first search (DFS) on a graph.

Hash Tables:

• Implement a hash map.
• Find the first non-repeating character in a string.
• Group anagrams from a list of strings.
• Find pairs in an array that sum to a specific target.

Heaps:

• Implement a min-heap or max-heap.
• Find the k largest/smallest elements in an array.
• Merge k sorted lists.

Dynamic Programming:

• Solve the Fibonacci sequence using dynamic programming.
• Implement the knapsack problem.
• Find the longest increasing subsequence.
• Solve the coin change problem.

2. Sorting and Searching

Sorting:

• Implement common sorting algorithms (quick sort, merge sort, bubble sort).
• Sort an array of strings by their lengths.
• Perform a custom sort based on given criteria.

Searching:

• Implement binary search in a sorted array.
• Find the first and last occurrence of an element in a sorted array.
• Search for an element in a rotated sorted array.

3. Recursion and Backtracking

Recursion:

• Solve the Tower of Hanoi problem.
• Generate all subsets of a set.
• Solve the N-Queens problem.

Backtracking:

• Solve the Sudoku puzzle.
• Find all permutations of a string or array.
• Generate all valid combinations of n pairs of parentheses.

4. Mathematical and Logical Puzzles

• Determine if a number is prime.
• Find the greatest common divisor (GCD) of two numbers.
• Implement a power function (x^n).

5. System Design and Object-Oriented Design (for more advanced or senior positions)

System Design:

• Design a URL shortening service.
• Design a scalable web crawler.
• Design an online bookstore.
• Design a distributed cache system.

Object-Oriented Design:

• Design a parking lot system.
• Design a library management system.
• Design a deck of cards.
• Design an elevator system.

Suggested Resource for Preparation

For a structured approach to learning and practicing these types of questions, consider using Grokking the Coding Interview: Patterns for Coding Questions from DesignGurus.io. This course focuses on recognizing and applying common coding patterns, which can help you solve a wide variety of problems efficiently.

Conclusion

In a coding interview, you can expect questions that test your knowledge of data structures, algorithms, sorting and searching techniques, recursion and backtracking, mathematical puzzles, and sometimes system and object-oriented design. By preparing for these types of questions and practicing regularly, you can build the skills and confidence needed to succeed in your coding interviews. Using structured resources like Grokking the Coding Interview from DesignGurus.io can help you prepare effectively by focusing on pattern recognition and problem-solving techniques.