Botkify – Music Playlist Manager Using Linked Lists

Project Overview

Botkify is a simulated music playlist management application implemented in C++.
The project demonstrates how linked list–based data structures can be applied to efficiently manage dynamic playlists and support advanced playback operations.

The system models playlists using a circular doubly linked list, enabling efficient insertion, deletion, and bidirectional traversal of songs. Additional features such as playlist scoring, randomized playback, and grouped evaluation are implemented using algorithmic techniques including monotonic stacks, sliding windows, and dynamic programming.

This project was developed as part of a Data Structures and Algorithms coursework to strengthen practical understanding of algorithm design, data structures, and modular programming.

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Key Features

Playlist Management

• Insert songs into the playlist
• Remove songs from the playlist
• Traverse playlist forward and backward
• Retrieve song metadata

Playback Simulation

• Play the next song
• Play the previous song
• Approximate playback using duration constraints

Playlist Analysis

• Compute playlist score
• Evaluate grouped songs
• Compare multiple playlists using scoring metrics

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Data Structures and Algorithms

The project integrates several algorithmic techniques to support efficient playlist operations.

Component	Technique
Playlist Representation	Circular Doubly Linked List
Playlist Traversal	Bidirectional Iteration
Score Computation	Monotonic Stack
Grouped Song Evaluation	Sliding Window
Approximate Playback	Dynamic Programming

These techniques ensure efficient execution while maintaining modular program design.

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Playlist Data Structure

The playlist is implemented using a circular doubly linked list, which enables efficient bidirectional traversal and continuous playback behavior.

        ┌───────────┐
        │  Song A   │
        └─────┬─────┘
              │ next
              ▼
        ┌───────────┐
        │  Song B   │
        └─────┬─────┘
              │ next
              ▼
        ┌───────────┐
        │  Song C   │
        └─────┬─────┘
              │
              ▼
           (back to Song A)

Traversal in reverse uses the `previous` pointers.

Each node stores:

• song information
• a pointer to the next node
• a pointer to the previous node

This design supports:

• O(1) traversal to the next or previous song
• efficient insertion and deletion
• continuous looping playback

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Playlist Operation Flow

Add Song
   ↓
Insert into Circular Doubly Linked List
   ↓
Update Playlist Structure
   ↓
Playback / Traversal
   ↓
Playlist Analysis (Scoring & Comparison)

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Example Usage

Example playlist operations:

Add Song: Song A
Add Song: Song B
Add Song: Song C

Current Playlist:
Song A → Song B → Song C

Play Next:
Now playing: Song B

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Project Structure

Botkify-Playlist-Linkedlist
│
├── src
│   ├── BotkifyLinkedList.h
│   ├── Playlist.h
│   ├── Playlist.cpp
│   ├── main.h
│   └── utils.h
│
├── tests
│   ├── doctest.h
│   ├── test_BotkifyLinkedList.cpp
│   └── test_play.cpp
│
├── main.cpp
├── Assignment 1 - Spec - EN.pdf
├── Assignment 1 - Spec - VI.pdf
├── .gitignore
└── README.md

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How to Compile and Run

Compile

g++ main.cpp -o botkify

Run

./botkify

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Algorithm Complexity

Operation	Time Complexity
addSong	O(1)
removeSong	O(n)
playNext / playPrevious	O(1)
calculatePlaylistScore	O(n)
getTotalScore	O(n²)

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Learning Outcomes

This project demonstrates:

• Practical implementation of linked list data structures
• Application of algorithmic techniques in playlist management
• Modular C++ programming and code organization
• Complexity analysis and algorithm optimization

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Author

Le Hien Vinh
Ho Chi Minh City University of Technology