How to generate a random sequence (permutation) of a finite sequence.

How to select k out of N objects.

max_heap: A[0] is the maximum value
min_heap: A[0] is the minimum value
source code: AC/Algorithms/Heap

I used to think deploying my blog with github actions is unnecessary, but now… (真香)
Deploying with github actions is so much faster.

My simple note on the RSA algorithm.

BIT can be used to compute the prefix sum of an array in $log(n)$ time and takes only $O(n)$ space.

source code

Use matrix and fast pow together can make some problems much easier.

knapsack problem and its variations

The Curses library forms a wrapper over working with raw terminal codes, and provides highly flexible and efficient API (Application Programming Interface). It provides functions to move the cursor, create windows, produce colors, play with mouse etc. The application programs need not worry about the underlying terminal capabilities

Description from wiki: a disjoint-set data structure, also called a union–find data structure or merge–find set, is a data structure that stores a collection of disjoint (non-overlapping) sets

you can easily solve leetcode: 547. Number of Provinces w/ UF.
get UF template at github/sky-bro/AC/Algorithms/Union Find

Easily compile and use multiple glibc on a single machine.

A de Bruijn sequence of order n on a size-k alphabet A is a cyclic sequence in which every possible length-n string on A occurs exactly once as a substring.

For a de Bruijn sequence of order n on a size-k alphabet $A$, we denote it by $B(k, n)$

A segment tree is a binary tree where each node represents an interval. Each node stores some property of its corresponding interval: like the maximum/minimum num, the sum of that interval.