This project provides some solutions to the Ninety-Nine Scala Problems.
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This project provides some solutions to the Ninety-Nine Scala Problems.


You can run the solutions via SBT:

$ sbt test

You can run a specific solution by specifying the full class name via:

$ sbt "test-only list.P01.sol01"

Recipes add a problem

Every problem belongs to a category. Every category (working with lists, arithmetic, logic and codes, binary trees, multiway trees, graphs, misc) has its own package. A problem and its solutions are regrouped in a subpackage of a category package. Then, the recipe is:

  1. Find the category package (or create it, if it does not exist)
  2. Create a subpackage referring to the problem (e.g., "P42")
  3. Create a trait for the problem that extends the trait "ExerciseTemplate"
  • Define in commentary the problem
  • Give a name to your problem by implementing the field "name"
  • Declare the prototype of the function that represents the solution
  • Write some tests ("ExerciceTemplate" extends "FunSuite" from scalatest)

It should look like:

package list.P01

import org.scalatest.FunSuite
import util.ExerciseTemplate

trait P01 extends ExerciseTemplate {
	P01 (*) Find the last element of a list.

    scala> last(List(1, 1, 2, 3, 5, 8))
    res0: Int = 8
  val name = "P01 (Find the last element of a list)"
  def last[T](l: List[T]): T

  // Tests
  test("Invoking last on non-empty lists should return the last element") {
    assert(8 == last(List(1, 1, 2, 3, 5, 8)))
    assert(69 == last(List(69)))

  test("Invoking last on an empty list should produce NoSuchElementException") {
    intercept[NoSuchElementException] {
} add a solution

Once a problem is created, you can add a solution. All you have to do is to implement in a class the trait that you have defined.


GPLv3 - see the COPYING file.