kotlin-polytech / kotlinasfirst

Задачи для онлайн-курса "Котлин как первый язык программирования"

Котлин как первый язык программирования

Решите приведённые в проекте задачи, чтобы научиться программировать на Котлине. Сейчас доступны двенадцать групп задач (уроков).

1. Простые функции.
2. Ветвления.
3. Циклы.
4. Работа со списками.
5. Работа с ассоциативными массивами (Maps).
6. Разбор строк.
7. Работа с файлами.
8. Простые классы.
9. Сложные классы на примере матриц.
10. Доп. главы (синтаксический разбор, Kotlin DSL).
11. Классы с арифметическими операциями.
12. Классы-контейнеры.

В директории tutorial имеется учебное пособие по Котлину на русском языке. Оно содержит введение и девять разделов, каждый из которых относится к соотвествующему уроку в проекте. Разделы 11 и 12 находятся в разработке. Также пособие включает дополнительные разделы, не включающие задач:

• 4.5 (про организацию памяти)
• 6.5 (про регулярные выражения)
• 8.5 (про графы и графовые алгоритмы)

Список использованных источников

Формулировки многих задач взяты из следующей книги:

• А. Юркин. Задачник по программированию. СПб.: Питер, 2002. - 192 с. ISBN 5-318-00399-0.

Полезные ссылки

Материалы по языку Kotlin:

• http://kotlinlang.org/docs/reference
• https://www.atomickotlin.com/atomickotlin

Видео-курс (Coursera):

• https://www.coursera.org/learn/vvedenie-v-yazyk-kotlin

Руководство по настройке среды программирования:

• http://kspt.icc.spbstu.ru/media/files/2021/kaf/KotlinAsFirstConfig.pdf

Задачи по алгоритмам (Java/Kotlin):

• https://github.com/Kotlin-Polytech/Algorithms

kotlinasfirst's Issues

Add lesson about container classes

Migrate to official code style

Think about evaluation system in 2017

In 2016 we had some issues about this. In particular, people tend to solve a lot of tasks in first lessons and then try to solve 1-2 easiest in second half.

Tests for lesson5.buildGrades

They should sort the function results

(2017) Create separate module for each lesson or even for each task

To be able to compile a lesson or a task regardless of other lessons / tasks current state

Write explicitly for all relevant lesson 3 task: do NOT use string functions

Add leading zeroes to lesson numbers

Most directory viewers now sort the lessons as following:

• lesson1
• lesson10
• lesson2
• lesson3
• ...
• lesson9

which is a bit frustrating.

Adding leading zeroes would solve this problem:

• lesson01
• lesson02
• lesson03
• ...
• lesson09
• lesson10

lesson5.task1.plusMinus: consider allowing signed numbers.

Currently, to strictly check input string for correctness a student has to perform two checks:

• try to call toInt() on number (to check format and integer range) and throw IllegalArgumentException if NumberFormatException happens;
• match with regex (something like [0-9]+) (to forbid signed numbers (+1, -7 etc.)), throw IAE if number does not match this regex.

Most students usually do not do at least one of those and it is rarely noted by teachers. A possible bug can only be found by random tests in some rare cases.

This can be solved two ways:

• provide some non random tests (like 1 + +3, 12 + -2, 121212121212121212121 + 3). (I'm not sure if JUnit's assertThrows will allow us to check if IAE but not NFE is thrown)
• consider the first two examples correct inputs (and everything accepted by .toInt()). (This way we have to update the model implementation since it tries to strictly check input string).

Switch on "use expression body" inspection

It currently has "no highlighting, fix only" status in 1.1.4 by default

Move lesson about files earlier

Reasons:

• it's needed for examination
• it's an advancement of lesson about text parsing (5)

Make lesson3.digitNumber easy, not trivial

Too much people solve it wrong in the first attempt

factorizeToString: divisors order

Clarify that divisros in factorizeToString should be in ascending order.

Add lesson about data-like classes

Clarify description of pow

In Kotlin 1.2+, pow is an extension and called as x.pow(y)

Add lesson about console applications with command line

Lesson should include task stubs, tests, and tutorial chapter. Probably it should have number 9, later we will discuss should we remove current lesson 7 or leave it as optional.

Add lessons or tasks about maps

It's useful in general, important for some file tasks (lesson 8), important for examination.

lesson5.task1: Reorder tasks by difficulty

Map lesson

Lesson 4: make roman numbers as in standard description

convertToString/decimalFromString: explicitly forbid to use stdlib functions

These tasks now can be solved using one line with standard library function which is probably not what we expect from students here.

Add test with squareBetweenExists with m or n as exact square

Kotlin Algorithm Club

Здравствуйте,
Я поддерживаю небольшой проект, посвящённый алгоритмам и структурам данных в kotlin. Возможно, он будет полезен в вашем курсе.
Ваш бывший студент =)

lesson5.task1.whoAreInBoth: specify behavior for lists with repeats

Update JUnit 5 version to release one

They had RC2 on July 30, soon we can expect release version

chapter04: лямбды

Нужно пояснение, почему параметр-лямбда не заключён в круглые скобки и когда это возможно.

Choose and attach license

Move task to lesson 3

Гипотеза Коллатца

/**
* Рекуррентная последовательность чисел задана следующим образом:
*
*   ЕСЛИ (X четное)
*     Xслед = X /2
*   ИНАЧЕ
*     Xслед = 3 * X + 1
*
* например
*   15 46 23 70 35 106 53 160 80 40 20 10 5 16 8 4 2 1 4 2 1 4 2 1 ...
* Данная последовательность рано или поздно встречает X == 1.
* Написать функцию, которая находит, сколько шагов требуется для
* этого для какого-либо начального X > 0.
*
* Имя функции и тип результата функции предложить самостоятельно.
*
* Кроме функции, следует написать тесты, 
* подтверждающие её работоспособность.
*/
fun myFun(x: Int): Any = TODO()

Add inspection configuration file to repo

And think a little bit about this configuration. For example, "LoopToCallChain" must be disabled.

dateStrToDigit/dateDigitToStr

Specify that day should be correct (e.g. 31.02.2001 and 29.02.2001 should be incorrect). Maybe enforce that with new task in lesson2 (daysInMonth(month: Int, year: Int))

Lesson 4: consider to convert Double to Int in tasks

This will help to stabilize tests, and in these tasks Double adds not so much to understanding something

Fix mostExpensive task

First, clarify that price can be without dot. Also, diagnostic message in tests should be fixed,

Migrate from Maven to Gradle

It's controversial but otherwise it's unclear how can we use inspection plugin. Some part of this work is already done in gradle branch.

Create fork for 2017 and move 2017.begin accordingly

Something like Kotoed2017. Better to wait until 04-09-2017 or something like this.

Clarify lesson7.task2.rotate

Should we rotate matrix in-place or return a copy?

Remove slides (and all relevant commits) from repo

May be, together with algorithm lessons, it will lead to migration to another repo, like KotoedCourse or so.

Clarify description and add shorter complex test for top20Words

• Clarify description: Is hello inside hello42 a word? (Not it's unclear if we should treat it as a word or just ignore it).
• Add test shorter than Eugene Onegin but that covers corner case (punctuation after word, Ё letter, hello42 case etc.)

Provide information about KiB, MiB, etc

Provide better reference list

May be it's a good idea to have one large reference list in README (and at some place of Coursera course(s)), and one shorter reference list per tutorial chapter.

Синхронизировать анаграммы с палиндромами

См. один из последних коммитов Кирилла

Lesson 6: some geometry data classes are broken

• Currently Line equality is broken. Point(α * x, α * y), angle + π * n for ∀α ∈ ℝ, ∀n ∈ ℤ represent the same line.
  k*x + b might work better but still isn't perfect ((-Inf) * x + b and (+Inf) * x + b represent the same line)
• Triangle and Segment equality comparison should be independent from the order of the points (for Segment it matters in diameter tests).

Line init block: replace assert with require

https://github.com/Kotlin-Polytech/KotlinAsFirst/blob/master/src/lesson6/task1/Geometry.kt#L120

Assertions are disabled in JVM by default and requireing is more correct.

clarify transliterate

What should we do with case in dictionary values when they are non-lower case? Should we call .capitalize() or .toLowerCase().capitalize()?

Random tests for lesson5.findCheapestStuff must consider the possibility of two things with the same price

Upgrade kotlin version to 1.1.4

After release

Add extra lessons for algorithms

See JavaKotlinASD repo.

Remove or fill TODO at the end of chapter 5

Update chapter 0 accordingly to infrastructure changes

chapter01: дискриминант

Для примера их использования рассмотрим решение задачи вычисления дискриминанта квадратного уравнения. Математически он равен квадратному корню из b²-4ac.

Дискриминант равен b²-4ac (не корню из), а при вычислении корней используется корень из дискриминанта.

Rename 'grad' to 'deg' in angleInRadian

Synchronize with test runner

Also better to wait until the beginning of September