In all our previous examples, we tried to solve either classification (predicting cats or dogs) or regression (predicting the average time users spend in the platform) problems. All these are examples of supervised learning, where the goal is to map the relationship between training examples and their targets and use it to make predictions on unseen data. 

Supervised learning is just one part of machine learning, and there are other different parts of machine learning. There are three different kinds of machine learning:

• Supervised learning
• Unsupervised learning
• Reinforcement learning

Let's look in detail at the kinds of algorithms.