Luogu P3174 题解：树上路径DP
题意给定一棵树，对于树上任意路径$P$，定义毛毛虫为点集 Read more
Luogu P1272：树形背包
树上, 状态必然有一个维度是“子树的根节点编号”, 记作$u$. 需要完全理解题意, 可构造出本题用$f(u,j)$来表示“将以$u$为根节点的子树拆成一棵大小是$j$的子树至少需要切断多少... Read more
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... 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