This repository provides implementations of popular machine learning and deep learning algorithms using four approaches: sklearn, Keras, PyTorch, and self-implementation from scratch. It covers regression, classification, neural networks (CNN, ResNet, LSTM), generative models (GAN), and deep reinforcement learning algorithms (DDPG, DQN, PPO, TRPO, actor-critic). The project aims to help learners understand both the practical usage and underlying theory of ML algorithms.