Interview Practice Problems

Below if a list of practice interview problems collected from various sources including Project Euler, random questions from Stack Overflow, and generally programming questions that I believe every computer science student should know. Each problem has one or more solutions in multiple languages. Feel free to discuss the solutions in the comments of each question. If you have any specific questions or languages that you would like me to support, please send me an email (you can find my email address on the contact page). The problems are arranged into three categories, “Beginner”, “Intermediate”, and “Advanced” and they are based upon my biased judgement.

Level 1 - Beginner

• Merge Sort - pythonruby

• Insert an Element into the Beginning of a Singly Linked List - java

• Insert an Element into a Singly Linked List - java

• Lookup an Element in a Singly Linked List - java

• Remove an Element from a Singly Linked List - java

• Append Two Singly Linked Lists - java

Level 2 - Intermediate

• One Stack, One Queue - python

• Reverse a Singly Linked List - java

Level 3 - Advanced

Topics that you should be familiar with:

This list is in no way comprehensive and it is a work-in-progress. I’ll try to update it as I think of new topics that are important to know.

• Data Structures - Pay attention to how the data structures are implemented, the runtimes for insert, lookup, and remove and you should understand the advantages of using one over the other. Also think about which scenarios it makes sense to use which data structure.
  • Singly Linked List
  • More Data Structures (with links to Wikipedia – I will write up my own versions when I have time)
    • Doubly-Linked List
    • Arrays
    • Hash Map (or Hash Table)
    • Graphs
    • General Trees
    • Radix Trees
    • Binary Search Trees
    • Binary Trees
    • Self-balanceing Binary Search Tree
    • Heaps
    • Binary Heaps
    • AVL Trees
  • You should also understand some abstract data types such as:
    • Stack
    • Queue
    • Priority Queue
  • Sorting - Another important thing to know is general sorting algorithms. For these, it is important to understand how they are implemented, what their use cases are, and the runtime of their operations.
    • Bubble Sort
    • Selection Sort
    • Insertion Sort
    • Merge Sort
    • Heap Sort
    • Quick Sort
    • Bucket Sort
    • Radix Sort
  • I’ll be adding more practice problems to the list above and also my own explanations for some of the data structures and sorting algorithms that I linked to above. As always, you can email me for any specific topics that you would like to me write about and explain for you.