Introduction

I want to start by clarifying that everything in this article is based on my personal experience working for about three years at a consulting company. I didn’t do any research, or reach out to other colleagues working with other companies, so some of the points may reflect my specific situation. That said, I believe many of the observations are broadly applicable and would likely hold true across different consulting environments. Also, I want to focus only on the IT & technology domain, as this is my work domain.

Background

In a previous project that I worked on, we had to connect to backend API using Qt framework in order to download some files and display some content of these files, this thing might look easily done using QNetworkAccessManager and QNetworkReply. But we had other things to consider:

• Size of the downloaded files was large.
• No file should be stored in the device running the application.

This is unofficial editorial for atCoder abc185.

What is Polygon

According to Polygon itself, The mission of Polygon is to provide platform for creation of programming contest problems. Polygon supports the whole development cycle:

• Problem statement writing.
• Test data preparing (generators supported).
• Model solutions (including correct and wittingly incorrect).
• Judging.
• Automatic validation.

This is unofficial editorial for atCoder abc179.

This is unofficial editorial for atCoder abc178.

I decided to write this article after watching the last screencast made by Errichto. To be more precise when he started making stress testing to find counter-test you can check that here. Errichto has a full video called How to test your solution in Competitive Programming, on Linux? I highly recommend you to check it, basically this article is the same but I am extending it to stress test solutions with multiple answers using a written checker, so let’s jump in.

Autocomplete

Autocomplete is the feature when an application predicts the complete word, after just typing some prefix of the word. You must have used autocomplete feature a lot in your life in many area like:

• Search engines, Google search engine suggests to you an autocomplete feature when you type some text in the search bar, usually sorted by most trends.
• Emails, as you start writing some prefix of the Email address you will get a list of suggestions.
• Social media, like facebook, linkedin, instagram…
• In source code editors, actually I am using Atom right now and I have used autocomplete for at least 10 times just in the first small part of this article.

Combinatorial Games

The game is said to be Combinatorial if it satisfies the following conditions:

1. The game is played between two players, we will call them Alice and Bob.
2. The two players alternate playing, Alice plays first.
3. We can define two sets \(F_1\) and \(F_2\) of possible moves for each player, these sets are usually finite, based on these two sets we can classify combinatorial games into:
   • Combinatorial impartial games this happens when \(F_1 = F_2\), this means both players have the same options of moving from each position.
   • Combinatorial partizan games this happens when \(F_1\ne F_2\), this includes games like chess or checkers in which one player moves the white pieces, and the other player moves the black pieces.
4. There is an end position of the game, usually called the terminal position. In normal play rule the player making the last move wins the game, in misère play rules the player making the last move loses the game.
5. The game always ends after some finite number of moves.

Introduction

The title contains a lot of terms that should be explained separately before we start, given an undirected graph \(G = (V, E)\) we define the following terms:

• Independent Set (IS) : Subset of nodes \(U \subseteq V\) with the following propriety: For any two nodes \(u, v \in U\) nodes \(u, v\) are not adjacent ( There is no direct edge between nodes \(u\) and \(v\) ).
• Maximal Independent Set (MIS) : An independent set is maximal if no node can be added to it without violating the independence condition.
• Maximum Independent Set (MaxIS) : An independent set of maximum cardinality.

Motivation Problem

Given \(n \times m\) matrix \((1 \le n, m \le 3*10^3)\) you have to calculate the sum of minimum numbers in all sub-matrices of size \(a\times b\) with top left corners in \((i, j)\) over all \(1 \le i \le n-a+1\) and \(1 \le j \le m-b+1\).

The term noise refers to unwanted electrical signal in electrical systems. This unwanted signal masks the information signal, limiting the transmission rate and affecting the receivers ability to make the correct symbol decision.

In communication systems noise arises due to different sources, these sources can be classified in two categories:

• Natural noise:
  • Atmospheric noise.
  • Noise from the sun.
  • Other galactic radiation sources.
• Man-made noise:
  • Ignition noise.
  • Radiating electromagnetic signals.

Motivation Problem

Given \(n \times m\) matrix \((1 \le n, m \le 3*10^3)\) you have to calculate the sum of minimum numbers in all sub-matrices of size \(a\times b\) with top left corners in \((i, j)\) over all \(1 \le i \le n-a+1\) and \(1 \le j \le m-b+1\).

The term noise refers to unwanted electrical signal in electrical systems. This unwanted signal masks the information signal, limiting the transmission rate and affecting the receivers ability to make the correct symbol decision.

In communication systems noise arises due to different sources, these sources can be classified in two categories:

• Natural noise:
  • Atmospheric noise.
  • Noise from the sun.
  • Other galactic radiation sources.
• Man-made noise:
  • Ignition noise.
  • Radiating electromagnetic signals.