Interactive Coding Challenges

Each challenge consists of two distinct notebooks designed to guide you through the learning process:

1. Challenge Notebook (For Practice)

This is where you solve the problem. It contains:

• Problem Statement: The description of the task.
• Constraints: Assumptions and limitations.
• Test Cases: Descriptions of general and edge cases.
• Algorithm: A placeholder section (refer to the solution notebook if stuck).
• Hints: On-demand incremental hints (rolling out).
• Code (Challenge: Implement Me!): Skeleton code for your implementation.
• Unit Test: A test suite that is expected to fail until your implementation is correct.

2. Solution Notebook (For Reference)

This provides the answers and deep dives. It contains:

• Algorithm: Detailed discussions of solutions including Big-O time and space complexities.
• Code (Challenge: Implement Me!): One or more complete reference solutions.
• Unit Test: The unit tests used to validate the reference solutions.

The repository is organized by data structure/algorithm categories. Each specific challenge is contained within its own folder following this pattern:

category_name/
└── challenge_name/
    ├── challenge_name_challenge.ipynb  # The interactive challenge
    ├── challenge_name_solution.ipynb  # The reference solution
    └── test_challenge_name.py          # The unit tests used by the notebook

interactive-coding-challenges        # Repo
├─ arrays_strings                    # Category of challenges
│  ├─ rotation                       # Challenge folder
│  │  ├─ rotation_challenge.ipynb    # Challenge notebook
│  │  ├─ rotation_solution.ipynb     # Solution notebook
│  │  ├─ test_rotation.py            # Unit test
│  ├─ compress
│  │  ├─ compress_challenge.ipynb
│  │  ├─ compress_solution.ipynb
│  │  ├─ test_compress.py
│  └─ ...
├─ linked_lists
│  ├─ palindrome
│  │  └─ ...
│  └─ ...
└─ ...

The repository contains a collection of interactive coding challenges focused on Arrays and Strings. Each challenge is provided as a Jupyter Notebook with two versions: a Challenge notebook for practice and a Solution notebook for reference. You can run these interactively using Binder or view them as static notebooks via NBViewer.

Available challenges include:

• Determine if a string contains unique characters
• Determine if a string is a permutation of another
• Determine if a string is a rotation of another
• Compress a string
• Reverse characters in a string
• Given two strings, find the single different char
• Find two indices that sum to a specific value
• Implement a hash table
• Implement fizz buzz

Some challenges (like 'Find the first non-repeated character in a string') are currently open for contribution.

<!-- Example of how to access a challenge via NBViewer -->
<a href="http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/unique_chars/unique_chars_challenge.ipynb">Challenge</a> │ <a href="http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/arrays_strings/unique_chars/unique_chars_solution.ipynb">Solution</a>

The repository provides interactive challenges for Graphs and Trees, accessible via static notebooks. You can use Binder to run these notebooks interactively in your browser.

Available challenges include:

• Implement depth-first search (pre-, in-, post-order) on a tree
• Implement breadth-first search on a tree
• Determine the height of a tree
• Create a binary search tree with minimal height from a sorted array
• Create a linked list for each level of a binary tree
• Check if a binary tree is balanced
• Determine if a tree is a valid binary search tree
• Find the in-order successor of a given node in a binary search tree
• Find the second largest node in a binary search tree
• Find the lowest common ancestor
• Invert a binary tree
• Implement a binary search tree
• Implement a min heap
• Implement a trie
• Implement depth-first search on a graph
• Implement breadth-first search on a graph
• Determine if there is a path between two nodes in a graph
• Implement a graph
• Find a build order given a list of projects and dependencies
• Find the shortest path in a weighted graph
• Find the shortest path in an unweighted graph