AVL树得名于它的发明者G. M. Adelson-Velsky和E. M. Landis，他们在1962年的论文《An algorithm for the organization of information》中发表了它。 --摘自百度百科
显然G. M. Adelson-Velsky贡献更大，是距今已有59年的老技术遗产。让人联想起同样拥有60多年历史的神经网络老模型理论，得益于现代硬件技术的提升，总算能够真正发挥实力，结果一鸣惊人，飞速发展。
小学生必知必会

Binary Sort Tree, 又称二叉搜索树，二叉查找树 Binary Search Tree。
出现时间可以追溯到计算机刚出现的年代，是几百年的遗产。属于幼儿园大班级别的数据结构知识。
思维结构极其简单，重在学习代码结构，与一些扩展算法应用。
幼儿园必知必会

"Collaborative filtering can be divided into users or items filtering. With its excellent speed and robustness, collaborative filtering is hot in the global Internet field. 😃😃"

Decision Tree is one of classical algorithms in machine learning. It can be used as both a classification model and a regression model. It is also suitable as a ensemble model, such as Random Forest. The history of Desicion Tree has three stages: ID3, C4.5 and CART

This is a summary of using logistic regression libraries in sklearn. Focus on the matters that should be paid attention to in the tuning.

"What is the lasso regression? Add L2 norm into loss function."

"Logistic Regression is a kind of very classical and basic classification algorithm."

"Linear Regression is the beginning and the most basic algorithm."

"A standard approach in regression analysis to approximate the solution of overdetermined systems."

When improving the model parameters of machine learning algorithms, that is, unconstrained optimalization problem.
Gradient Descent method is one of most common used methods. The other one is the least square method. Here is a complete summary of the gradient descent method.