"Used my FAANG companies to train people
Leetcode is an online resource that is geared towards teaching people how to code and solve problems specifically geared toward Silicon Valley type companies, Amazon, Google, Facebook, etc. FAANG et al.
Many see this as a positive, while others see the interview tactics as something of a memorization game.
Either way, Leetcode provides many hundreds of coding exercises and tests to learn about advanced programming methodology and approaches.