题解 CF55D ：数位DP+数论
这题做了半天。美丽的数的定义是“可以被自己的所有非零数位整除的数”。做数位DP，想的就是每个状态需要什么参量来表示。注意到这个定义的限制并不在选取每个数位的时候，而是... Read more
题解 CF628D：数位DP
很显然是数位DP了。 Read more
Four OOP Implementations in JavaScript
This article compares and contrasts four different implementations of object-oriented programming in JavaScript. Read more
Support Vector Machines
We could use KNN, logistic regression, LDA, and decision trees for classification problems. Here we discuss a new set of methods: the maximal margin classifier, the support vector classifier, and the support vector machine, which are often loosely referred to as “support vector machines”. Read more
Tree-Based Methods
Recall that we use step functions, where the range of predictor $X$ is broken into several bins and in each bin the average of the observed response, certainly a constant, is used as the prediction. Step functions can be viewed as a special case of tree-based methods, the latter of which could be applied to multiple predictors. Read more
Non-Linear Models
Linear models, including linear regression and models making improvements on it, can only offer a limited approximation of the real world. Therefore, moving beyond linearity is necessitated in various situations where more flexibility is required. Read more