There are some interesting algorithms in simulation from Physics, Chemistry, and Engineering especially regarding Monte Carlo simulation: Heat Bath algorithm, Metro-Police algorithm, Markov Chain Monte Carlo, etc.

https://github.com/trekhleb/javascript-algorithms/blob/master/src/algorithms/sets/cartesian-product/cartesianProduct.js#L8

I think it makes more sense to return an empty array

// invalid input return null or throw an error
if (!setA || !setB) {
    return null;
}
if (!setA.length || !setB.length) {
    return []; 
}
// or do nothing since the for loop will not trigger anyway

• We have BFS and DFS images in both Breadth First Traversal and Depth First Traversal. We should have illustrations in the respective sections.

Hey Yangshun,
Thanks for the great list of guides!

I found the explanation for Snake game bit difficult to follow and I came across this interesting and better explanantion here https://www.youtube.com/watch?v=AaGK-fj-BAM

有一幅以二维整数数组表示的图画，每一个整数表示该图画的像素值大小，数值在 0 到 65535 之间。

给你一个坐标 (sr, sc) 表示图像渲染开始的像素值（行 ，列）和一个新的颜色值 newColor，让你重新上色这幅图像。

为了完成上色工作，从初始坐标开始，记录初始坐标的上下左右四个方向上像素值与初始坐标相同的相连像素点，接着再记录这四个方向上符合条件的像素点与他们对应四个方向上像素值与初始坐标相同的相连像素点，……，重复该过程。将所有有记录的像素点的颜色值改为新的颜色值。

最后返回经过上色渲染后的图像。

示例 1:

输入:
image = [[1,1,1],[1,1,0],[1,0,1]]
sr = 1, sc = 1, newColor = 2
输出: [[2,2,2],[2,2,0],[2,0,1]]
解析:
在图像的正中间，(坐标(

Selection Sort, for example, makes the algorithm look extremely (impossibly) good at first glance - O(n) - because it's not showing the majority of the steps.

Instead of

    for (var j = i + 1; j < D.length; j++) {
        if (D[j] < D[minJ]) {
            tracer._select(j);
            minJ = j;
            tracer._deselect(j);
        }
    }

it has to be more like

    for (var j

https://mybinder.org/ Should I make a binder ? :) Or if there is a binder link, it's well hidden.

Is there a reason why in travis CI config the command black --check . || true is run? I don't see the point in checking if files needs to be reformatted if it's just going to be ignored anyways.

Currently running black --line-length 127 --check . -> 399 files would be reformatted, 74 files would be left unchanged.

In additio

Vectorized version of gradient descent.

theta = theta * reg_param - alpha * (1 / num_examples) * (delta.T @ self.data).T

We should NOT regularize the parameter theta_zero.

theta[0] = theta[0] - alpha * (1 / num_examples) * (self.data[:, 0].T @ delta).T

the first code line ,theta include theta[0].
so I think can write like this:
theta[0] -= alpha * (1 / num_examples) * (self.data[:, 0].

This is a(n):

• New algorithm
• Update to an existing algorithm
• Error
• Proposal to the Repository

Details:

We can make a file may be READ.

Chapter number or note title: Chapter 0, Exercise 2, Footnote 24

Page number: 17

Error description: The footnote says "Ja, das ist das [...]maschine". However, the German language has 3 different articles (der, die das). In this particular case, you want "die" instead of "das" [...]maschine.

Suggested fix (if any):
Ja, das ist die Subatomar[...]maschine.

Hey @mgechev,
I noticed that you have a README.md file in src/sorting, which has the Big O complexity for all algorithms. It also has the "When to use" column, which is blank. Basecs already has many algorithms' explanations, and can be used to fill in this.column. The explanations are valid for most languages and are concise.

Also, a README.md for all src/* folders would be helpful. (I would

🚀 Feature Proposal

Adding leading zero in the question number will be an awesome feature for file explorer to sort files by the name.

test with turf.lineString(<coords>,{},{id:0})
on v.5.1.6

if id is 0 the id field is missing

A more consistent and multi-functional global level of verbosity control,
suggest an enhancement that will see print(...) in project be converted to using the python logging. module

import logging
#Then instead of print() use either
logging.info(......)
#or
logging.debug(.....)
#or
logging.warning(....)
#or
#logging.error()

In that way verbosity can be globally

Add quickselect algorithm. Quickselect is a selection algorithm to find the kth smallest element in an unordered list.