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Add practice exercise piecing-it-together (#1576)
* Add practice exercise `piecing-it-together` * practive integers and floats Co-authored-by: Angelika Cathor <angelikatyborska@fastmail.com> * fix doc * add prerequisites * integers already practiced 10 times * add nils to struct types * do not nest module * Fix module name in mix.exs --------- Co-authored-by: Angelika Cathor <angelikatyborska@fastmail.com> Co-authored-by: Angelika Cathor <angelikacathor@fastmail.com>
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‎config.json‎

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],
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"difficulty": 7
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},
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{
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"slug": "piecing-it-together",
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"name": "Piecing It Together",
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"uuid": "e20ce41a-ff3f-46e4-9fbb-8810883c488f",
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"practices": [
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"structs",
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"floating-point-numbers"
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],
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"prerequisites": [
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"structs",
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"errors",
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"multiple-clause-functions",
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"pattern-matching",
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"guards",
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"if",
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"case",
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"integers",
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"floating-point-numbers",
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"maps",
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"enum",
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"keyword-lists",
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"erlang-libraries"
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],
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"difficulty": 7
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},
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{
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"slug": "queen-attack",
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"name": "Queen Attack",

‎exercises/practice/piecing-it-together/.docs/instructions.md‎

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# Instructions
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Given partial information about a jigsaw puzzle, add the missing pieces.
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If the information is insufficient to complete the details, or if given parts are in contradiction, the user should be notified.
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The full information about the jigsaw puzzle contains the following parts:
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- `pieces`: Total number of pieces
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- `border`: Number of border pieces
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- `inside`: Number of inside (non-border) pieces
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- `rows`: Number of rows
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- `columns`: Number of columns
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- `aspectRatio`: Aspect ratio of columns to rows
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- `format`: Puzzle format, which can be `portrait`, `square`, or `landscape`
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For this exercise, you may assume square pieces, so that the format can be derived from the aspect ratio:
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- If the aspect ratio is less than 1, it's `portrait`
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- If it is equal to 1, it's `square`
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- If it is greater than 1, it's `landscape`
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## Three examples
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### Portrait
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A portrait jigsaw puzzle with 6 pieces, all of which are border pieces and none are inside pieces. It has 3 rows and 2 columns. The aspect ratio is 1.5 (3/2).
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![A 2 by 3 jigsaw puzzle](https://assets.exercism.org/images/exercises/piecing-it-together/jigsaw-puzzle-2x3.svg)
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### Square
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A square jigsaw puzzle with 9 pieces, all of which are border pieces except for the one in the center, which is an inside piece. It has 3 rows and 3 columns. The aspect ratio is 1 (3/3).
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![A 3 by 3 jigsaw puzzle](https://assets.exercism.org/images/exercises/piecing-it-together/jigsaw-puzzle-3x3.svg)
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### Landscape
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A landscape jigsaw puzzle with 12 pieces, 10 of which are border pieces and 2 are inside pieces. It has 3 rows and 4 columns. The aspect ratio is 1.333333... (4/3).
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![A 4 by 3 jigsaw puzzle](https://assets.exercism.org/images/exercises/piecing-it-together/jigsaw-puzzle-4x3.svg)

‎exercises/practice/piecing-it-together/.docs/introduction.md‎

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# Introduction
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Your best friend has started collecting jigsaw puzzles and wants to build a detailed catalog of their collection — recording information such as the total number of pieces, the number of rows and columns, the number of border and inside pieces, aspect ratio, and puzzle format.
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Even with your powers combined, it takes multiple hours to solve a single jigsaw puzzle with one thousand pieces — and then you still need to count the rows and columns and calculate the remaining numbers manually.
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The even larger puzzles with thousands of pieces look quite daunting now.
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"There has to be a better way!" you exclaim and sit down in front of your computer to solve the problem.

‎exercises/practice/piecing-it-together/.formatter.exs‎

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# Used by "mix format"
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[
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inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"]
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]

‎exercises/practice/piecing-it-together/.gitignore‎

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# The directory Mix will write compiled artifacts to.
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/_build/
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# If you run "mix test --cover", coverage assets end up here.
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/cover/
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# The directory Mix downloads your dependencies sources to.
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/deps/
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# Where third-party dependencies like ExDoc output generated docs.
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/doc/
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# Ignore .fetch files in case you like to edit your project deps locally.
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/.fetch
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# If the VM crashes, it generates a dump, let's ignore it too.
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erl_crash.dump
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# Also ignore archive artifacts (built via "mix archive.build").
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*.ez
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# Ignore package tarball (built via "mix hex.build").
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piecing_it_together-*.tar
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# Temporary files, for example, from tests.
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/tmp/

‎exercises/practice/piecing-it-together/.meta/config.json‎

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{
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"authors": [
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"jiegillet"
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],
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"files": {
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"solution": [
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"lib/jigsaw_puzzle.ex"
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],
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"test": [
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"test/jigsaw_puzzle_test.exs"
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],
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"example": [
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".meta/example.ex"
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]
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},
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"blurb": "Fill in missing jigsaw puzzle details from partial data",
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"source": "atk just started another 1000-pieces jigsaw puzzle when this idea hit him",
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"source_url": "https://github.com/exercism/problem-specifications/pull/2554"
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}

‎exercises/practice/piecing-it-together/.meta/example.ex‎

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defmodule JigsawPuzzle do
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@doc """
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Fill in missing jigsaw puzzle details from partial data
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"""
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@type format() :: :landscape | :portrait | :square
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@type t() :: %__MODULE__{
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pieces: pos_integer() | nil,
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rows: pos_integer() | nil,
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columns: pos_integer() | nil,
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format: format() | nil,
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aspect_ratio: float() | nil,
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border: pos_integer() | nil,
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inside: pos_integer() | nil
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}
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defstruct [:pieces, :rows, :columns, :format, :aspect_ratio, :border, :inside]
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@spec data(jigsaw_puzzle :: JigsawPuzzle.t()) ::
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{:ok, JigsawPuzzle.t()} | {:error, String.t()}
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def data(%JigsawPuzzle{} = jigsaw_puzzle) do
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jigsaw_puzzle
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|> Map.from_struct()
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|> Enum.filter(fn {_, value} -> value end)
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|> Enum.sort_by(fn {key, _} -> key end)
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|> complete_data()
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end
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defp complete_data(aspect_ratio: aspect_ratio, pieces: pieces) do
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columns = round(:math.sqrt(aspect_ratio * pieces))
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rows = Integer.floor_div(pieces, columns)
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border = 2 * (rows + columns) - 4
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inside = pieces - border
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: aspect_ratio_to_format(aspect_ratio),
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aspect_ratio: aspect_ratio,
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border: border,
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inside: inside
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}}
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end
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defp complete_data(format: :square, rows: rows) do
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columns = rows
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pieces = rows * columns
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border = 2 * (rows + columns) - 4
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inside = pieces - border
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: :square,
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aspect_ratio: 1.0,
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border: border,
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inside: inside
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}}
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end
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defp complete_data(format: _, rows: _) do
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{:error, "Insufficient data"}
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end
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defp complete_data(aspect_ratio: 1.0, inside: inside) do
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columns = 2 + round(:math.sqrt(inside))
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rows = columns
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pieces = rows * columns
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border = pieces - inside
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: :square,
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aspect_ratio: 1.0,
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border: border,
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inside: inside
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}}
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end
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defp complete_data(aspect_ratio: _, inside: _) do
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{:error, "Insufficient data"}
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end
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defp complete_data(aspect_ratio: aspect_ratio, rows: rows) do
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columns = round(rows * aspect_ratio)
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pieces = rows * columns
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border = 2 * (rows + columns) - 4
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inside = pieces - border
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: aspect_ratio_to_format(aspect_ratio),
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aspect_ratio: aspect_ratio,
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border: border,
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inside: inside
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}}
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end
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defp complete_data(border: border, format: :square, pieces: pieces) do
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complete_data(aspect_ratio: 1.0, inside: pieces - border)
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end
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defp complete_data(border: border, format: format, pieces: pieces) do
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center = 1 + border / 4
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diff = :math.sqrt(center ** 2 - pieces)
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{rows, columns} =
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case format do
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:landscape -> {round(center - diff), round(center + diff)}
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:portrait -> {round(center + diff), round(center - diff)}
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end
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aspect_ratio = columns / rows
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inside = pieces - border
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: format,
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aspect_ratio: aspect_ratio,
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border: border,
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inside: inside
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}}
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end
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defp complete_data(columns: columns, format: format, rows: rows) do
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aspect_ratio = columns / rows
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if format == aspect_ratio_to_format(aspect_ratio) do
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pieces = rows * columns
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border = 2 * (rows + columns) - 4
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inside = rows * columns - border
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{:ok,
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%JigsawPuzzle{
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pieces: pieces,
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rows: rows,
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columns: columns,
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format: format,
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aspect_ratio: aspect_ratio,
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border: border,
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inside: inside
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}}
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else
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{:error, "Contradictory data"}
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end
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end
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defp complete_data(_) do
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{:error, "Insufficient data"}
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end
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defp aspect_ratio_to_format(aspect_ratio) do
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case aspect_ratio do
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aspect_ratio when aspect_ratio < 1 -> :portrait
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aspect_ratio when aspect_ratio > 1 -> :landscape
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_ -> :square
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end
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end
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end

‎exercises/practice/piecing-it-together/.meta/tests.toml‎

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# This is an auto-generated file.
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#
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# Regenerating this file via `configlet sync` will:
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# - Recreate every `description` key/value pair
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# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
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# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
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# - Preserve any other key/value pair
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#
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# As user-added comments (using the # character) will be removed when this file
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# is regenerated, comments can be added via a `comment` key.
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[ad626f23-09a2-4f5f-ba22-eec0671fa2a9]
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description = "1000 pieces puzzle with 1.6 aspect ratio"
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[3e0c5919-3561-42f5-b9ed-26d70c20214e]
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description = "square puzzle with 32 rows"
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[1126f160-b094-4dc2-bf37-13e36e394867]
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description = "400 pieces square puzzle with only inside pieces and aspect ratio"
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[a9743178-5642-4cc0-8fdb-00d6b031c3a0]
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description = "1500 pieces landscape puzzle with 30 rows and 1.6 aspect ratio"
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[f6378369-989c-497f-a6e2-f30b1fa76cba]
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description = "300 pieces portrait puzzle with 70 border pieces"
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[f53f82ba-5663-4c7e-9e86-57fdbb3e53d2]
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description = "puzzle with insufficient data"
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[a3d5c31a-cc74-44bf-b4fc-9e4d65f1ac1a]
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description = "puzzle with contradictory data"

‎exercises/practice/piecing-it-together/lib/jigsaw_puzzle.ex‎

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defmodule JigsawPuzzle do
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@doc """
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Fill in missing jigsaw puzzle details from partial data
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"""
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@type format() :: :landscape | :portrait | :square
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@type t() :: %__MODULE__{
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pieces: pos_integer() | nil,
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rows: pos_integer() | nil,
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columns: pos_integer() | nil,
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format: format() | nil,
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aspect_ratio: float() | nil,
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border: pos_integer() | nil,
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inside: pos_integer() | nil
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}
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defstruct [:pieces, :rows, :columns, :format, :aspect_ratio, :border, :inside]
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@spec data(jigsaw_puzzle :: JigsawPuzzle.t()) ::
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{:ok, JigsawPuzzle.t()} | {:error, String.t()}
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def data(jigsaw_puzzle) do
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end
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end

‎exercises/practice/piecing-it-together/mix.exs‎

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defmodule JigsawPuzzle.MixProject do
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use Mix.Project
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def project do
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[
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app: :piecing_it_together,
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version: "0.1.0",
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start_permanent: Mix.env() == :prod,
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deps: deps()
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]
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end
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# Run "mix help compile.app" to learn about applications.
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def application do
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[
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extra_applications: [:logger]
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]
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end
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# Run "mix help deps" to learn about dependencies.
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defp deps do
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[
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# {:dep_from_hexpm, "~> 0.3.0"},
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# {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
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]
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end
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end

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