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SergiiVlasiuk's solution

to Series in the Scala Track

Published at Aug 26 2019 · 0 comments
Instructions
Test suite
Solution

Given a string of digits, output all the contiguous substrings of length n in that string.

For example, the string "49142" has the following 3-digit series:

  • 491
  • 914
  • 142

And the following 4-digit series:

  • 4914
  • 9142

And if you ask for a 6-digit series from a 5-digit string, you deserve whatever you get.

Note that these series are only required to occupy adjacent positions in the input; the digits need not be numerically consecutive.

The Scala exercises assume an SBT project scheme. The exercise solution source should be placed within the exercise directory/src/main/scala. The exercise unit tests can be found within the exercise directory/src/test/scala.

To run the tests simply run the command sbt test in the exercise directory.

For more detailed info about the Scala track see the help page.

Source

A subset of the Problem 8 at Project Euler http://projecteuler.net/problem=8

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

SeriesTest.scala

import org.scalatest.{Matchers, FunSuite}

/** @version created manually **/
class SeriesTest extends FunSuite with Matchers {

  test("slices of one") {
    Series.slices(1, "") should be (List())
    Series.slices(1, "01234") should be (List(List(0), List(1), List(2),
      List(3), List(4)))
  }

  test("slices of two") { 
    pending
    Series.slices(2, "") should be (List())
    Series.slices(2, "01") should be (List(List(0, 1)))
    Series.slices(2, "01234") should be (List(List(0, 1), List(1, 2), List(2, 3),
      List(3, 4)))
  }

  test("slices of three") { 
    pending
    Series.slices(3, "") should be (List())
    Series.slices(3, "012") should be (List(List(0, 1, 2)))
    Series.slices(3, "01234") should be (List(List(0, 1, 2), List(1, 2, 3),
      List(2, 3, 4)))
  }
}
object Series {
  def slices(count: Int, number: String) = number map (_.asDigit) sliding (count) toList
}

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