A description is incomplete. It should mention:

These patterns are not competing, but complementing each other. To achieve availability, one needs both fail-over and replication.

right after

"There are two main patterns to support high availability: fail-over and replication. "

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.

一个班级60%喜欢足球，70%喜欢篮球，80%喜欢排球，问：三种球都喜欢占比最大可能有多少，最小可能有多少？即求三种球都喜欢的比例范围

Contributing.md doesn't doesn't appear to contain any actual guidlines, and the link only leads back to the same document: Java/CONTRIBUTING.md.

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

要求：

1、只能修改 setTimeout 到 Math.floor(Math.random() * 1000 的代码

2、不能修改 Math.floor(Math.random() * 1000

3、不能使用全局变量

function print(n){
  setTimeout(() => {
    console.log(n);
  }, Math.floor(Math.random() * 1000));
}
for(var i = 0; i < 100; i++){
  print(i);
}

🚀 Feature Proposal

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

This is a reminder for me or a task if anyone wants :P

Basically, The last two questions aren't really regex's questions.

To do:

• Move said questions to correct place.
• Add new regex questions (Python related!)?
• Maybe add a new ## Regex section, as it is a valuable skill