leetcode

LeetCode & DSA Practice

Structured practice for LeetCode concepts with lessons, practice problems, and interactive visualizations.

Quick Start

Run a solution:

cd python/leetcode && python problems/two_sum/python/solved/two-sum-solved.py

Launch the Learning Labs GUI:

cd python/leetcode && python launch_learning_labs.py

On macOS you can also double-click launch.command.

Problems

Problem	Difficulty	Pattern	Status
Two Sum	Easy	Hashmap	✅ Solved
Add Two Numbers	Medium	Linked List	✅ Solved
Longest Substring	Medium	Sliding Window	✅ Solved

Each problem folder contains:

• lesson/ - Detailed explanations and approach
• practice/ - Practice variants to reinforce learning
• solved/ - Complete solutions

Learning Labs

Interactive PyQt6 application for visualizing algorithms step-by-step.

The app currently includes Two Sum and Add Two Numbers exercises with helpers for visualizing inputs and outputs.

Progress

Completed:

• ✅ Two Sum (Easy) - hashmap approach
• ✅ Add Two Numbers (Medium) - linked list with carry
• ✅ Longest Substring (Medium) - sliding window

Structure

leetcode/
├── problems/                    # Individual LeetCode problems
│   ├── two_sum/
│   ├── add_two_numbers/
│   └── longest_substring/
├── pyqt6_learning_labs/         # Interactive GUI application
├── index.md                     # Progress tracking
├── launch_learning_labs.py      # GUI launcher
└── PYQT6_APPS_AUDIT.md          # App development notes