Jerry Blog

Think like a Bayesian, worry like a frequentist.

Founadation of Machine Learning Part I

Supervised Learning Setup Let us formalize the supervised machine learning setup. Our training data comes in pairs of inputs $(x,y)$, where $x∈R_d$ is the input instance and y its label. The entir...

Posted by Jerry Liu on March 26, 2019

Optimization

Numerical optimization is at the core of much of machine learning. Gradient Descent That’s not hard, we just jump to the conclusion. To minimize the function \(f\), We update the value with ...

Posted by Jerry Liu on March 23, 2019

LeetCode 94 Binary Tree Inorder Traversal

Description Given a binary tree, return the inorder traversal of its nodes’ values. Here the inorder means [left root right]. LeetCode here. Recursive Solution It’s quite easy, we jump to the co...

Posted by Jerry Liu on March 23, 2019

LeetCode 145 Binary Tree Postorder Traversal

Description Given a binary tree, return the postorder traversal of its nodes’ values. Here the inorder means [left right root]. LeetCode here. Recusive Solution It’s quite easy, we jump to the c...

Posted by Jerry Liu on March 23, 2019

EXISTS function in SQL

Logic of EXISTS EXISTS is a frequently used SQL function. EXISTS will return the boolean value whether the condition is satisfied or not. For example, suppose we have the following tables: ...

Posted by Jerry Liu on March 18, 2019