Add word-search exercise

config.json

@@ -615,6 +615,14 @@
         "prerequisites": [],
         "difficulty": 6
       },
+      {
+        "slug": "word-search",
+        "name": "Word Search",
+        "uuid": "6e00fa23-6f9c-412b-9cc4-f257158c8f64",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 6
+      },
       {
         "slug": "bowling",
         "name": "Bowling",

exercises/practice/word-search/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Instructions
+
+In word search puzzles you get a square of letters and have to find specific words in them.
+
+For example:
+
+```text
+jefblpepre
+camdcimgtc
+oivokprjsm
+pbwasqroua
+rixilelhrs
+wolcqlirpc
+screeaumgr
+alxhpburyi
+jalaycalmp
+clojurermt
+```
+
+There are several programming languages hidden in the above square.
+
+Words can be hidden in all kinds of directions: left-to-right, right-to-left, vertical and diagonal.
+
+Given a puzzle and a list of words return the location of the first and last letter of each word.

exercises/practice/word-search/.meta/Example.roc

@@ -0,0 +1,63 @@
+module [search]
+
+Position : { column : U64, row : U64 }
+WordLocation : { start : Position, end : Position }
+
+## Pad each row with spaces to ensure all rows have the same width
+padRight : List (List U8) -> { rows : List (List U8), width : U64 }
+padRight = \grid ->
+    width = grid |> List.map List.len |> List.max |> Result.withDefault 0
+    padSpaces = \chars -> List.repeat ' ' (width - List.len chars)
+    {
+        rows: grid |> List.map \chars -> chars |> List.concat (padSpaces chars),
+        width,
+    }
+
+getChar : List (List U8), U64, U64 -> U8
+getChar = \grid, columnIndex, rowIndex ->
+    grid
+    |> List.get rowIndex
+    |> Result.withDefault []
+    |> List.get columnIndex
+    |> Result.withDefault ' '
+
+search : Str, List Str -> Dict Str WordLocation
+search = \grid, wordsToSearchFor ->
+    { rows, width } = grid |> Str.split "\n" |> List.map Str.toUtf8 |> padRight
+    height = List.len rows
+    heightI64 = height |> Num.toI64
+    widthI64 = width |> Num.toI64
+    maxLength = Num.max width height |> Num.toI64
+    # for all possible starting positions:
+    List.range { start: At 0, end: Before width }
+    |> List.joinMap \columnIndex ->
+        List.range { start: At 0, end: Before height }
+        |> List.joinMap \rowIndex ->
+            # for all possible directions:
+            [(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), (1, 1)]
+            |> List.joinMap \(dirColumn, dirRow) ->
+                start = { column: columnIndex + 1, row: rowIndex + 1 }
+                # for all possible lengths:
+                List.range { start: At 0, end: Before maxLength } # for all possible words starting at the given position and
+                # going in the given direction, take note of the start and end
+                # positions
+                |> List.walkUntil { foundWords: [], chars: [] } \state, index ->
+                    endColumnIndex = Num.toI64 columnIndex + dirColumn * index
+                    endRowIndex = Num.toI64 rowIndex + dirRow * index
+                    if endColumnIndex < 0 || endColumnIndex >= widthI64 || endRowIndex < 0 || endRowIndex >= heightI64 then
+                        Break state
+                        else
+
+                    endColumnIndexU64 = endColumnIndex |> Num.toU64
+                    endrowIndexU64 = endRowIndex |> Num.toU64
+                    char = rows |> getChar endColumnIndexU64 endrowIndexU64
+                    newChars = state.chars |> List.append char
+                    end = { column: endColumnIndexU64 + 1, row: endrowIndexU64 + 1 }
+                    maybeWord = wordsToSearchFor |> List.findFirst \word -> word |> Str.toUtf8 == newChars
+                    newFoundWords =
+                        when maybeWord is
+                            Ok word -> state.foundWords |> List.append (word, { start, end })
+                            Err NotFound -> state.foundWords
+                    Continue { foundWords: newFoundWords, chars: newChars }
+                |> .foundWords
+    |> Dict.fromList

exercises/practice/word-search/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [
+    "ageron"
+  ],
+  "files": {
+    "solution": [
+      "WordSearch.roc"
+    ],
+    "test": [
+      "word-search-test.roc"
+    ],
+    "example": [
+      ".meta/Example.roc"
+    ]
+  },
+  "blurb": "Create a program to solve a word search puzzle."
+}

exercises/practice/word-search/.meta/template.j2

@@ -0,0 +1,24 @@
+{%- import "generator_macros.j2" as macros with context -%}
+{{ macros.canonical_ref() }}
+{{ macros.header() }}
+
+import {{ exercise | to_pascal }} exposing [{{ cases[0]["property"] | to_camel }}]
+
+{% for case in cases -%}
+# {{ case["description"] }}
+expect
+    grid = {{ case["input"]["grid"] | to_roc_multiline_string | indent(8) }}
+    wordsToSearchFor = {{ case["input"]["wordsToSearchFor"] | to_roc }}
+    result = grid |> {{ case["property"] | to_camel }} wordsToSearchFor
+    expected = Dict.fromList [
+    {%- for word, result in case["expected"].items() %}
+        {%- if result is none %}
+        # {{ word | to_roc }} is not in the grid
+        {%- else %}
+        ({{ word | to_roc }}, {{ result | to_roc }}),
+        {%- endif %}
+    {%- endfor %}
+    ]
+    result == expected
+
+{% endfor %}

exercises/practice/word-search/.meta/tests.toml

@@ -0,0 +1,82 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[b4057815-0d01-41f0-9119-6a91f54b2a0a]
+description = "Should accept an initial game grid and a target search word"
+
+[6b22bcc5-6cbf-4674-931b-d2edbff73132]
+description = "Should locate one word written left to right"
+
+[ff462410-434b-442d-9bc3-3360c75f34a8]
+description = "Should locate the same word written left to right in a different position"
+
+[a02febae-6347-443e-b99c-ab0afb0b8fca]
+description = "Should locate a different left to right word"
+
+[e42e9987-6304-4e13-8232-fa07d5280130]
+description = "Should locate that different left to right word in a different position"
+
+[9bff3cee-49b9-4775-bdfb-d55b43a70b2f]
+description = "Should locate a left to right word in two line grid"
+
+[851a35fb-f499-4ec1-9581-395a87903a22]
+description = "Should locate a left to right word in three line grid"
+
+[2f3dcf84-ba7d-4b75-8b8d-a3672b32c035]
+description = "Should locate a left to right word in ten line grid"
+
+[006d4856-f365-4e84-a18c-7d129ce9eefb]
+description = "Should locate that left to right word in a different position in a ten line grid"
+
+[eff7ac9f-ff11-443e-9747-40850c12ab60]
+description = "Should locate a different left to right word in a ten line grid"
+
+[dea39f86-8c67-4164-8884-13bfc48bd13b]
+description = "Should locate multiple words"
+
+[29e6a6a5-f80c-48a6-8e68-05bbbe187a09]
+description = "Should locate a single word written right to left"
+
+[3cf34428-b43f-48b6-b332-ea0b8836011d]
+description = "Should locate multiple words written in different horizontal directions"
+
+[2c8cd344-a02f-464b-93b6-8bf1bd890003]
+description = "Should locate words written top to bottom"
+
+[9ee1e43d-e59d-4c32-9a5f-6a22d4a1550f]
+description = "Should locate words written bottom to top"
+
+[6a21a676-f59e-4238-8e88-9f81015afae9]
+description = "Should locate words written top left to bottom right"
+
+[c9125189-1861-4b0d-a14e-ba5dab29ca7c]
+description = "Should locate words written bottom right to top left"
+
+[b19e2149-7fc5-41ec-a8a9-9bc6c6c38c40]
+description = "Should locate words written bottom left to top right"
+
+[69e1d994-a6d7-4e24-9b5a-db76751c2ef8]
+description = "Should locate words written top right to bottom left"
+
+[695531db-69eb-463f-8bad-8de3bf5ef198]
+description = "Should fail to locate a word that is not in the puzzle"
+
+[fda5b937-6774-4a52-8f89-f64ed833b175]
+description = "Should fail to locate words that are not on horizontal, vertical, or diagonal lines"
+
+[5b6198eb-2847-4e2f-8efe-65045df16bd3]
+description = "Should not concatenate different lines to find a horizontal word"
+
+[eba44139-a34f-4a92-98e1-bd5f259e5769]
+description = "Should not wrap around horizontally to find a word"
+
+[cd1f0fa8-76af-4167-b105-935f78364dac]
+description = "Should not wrap around vertically to find a word"

exercises/practice/word-search/WordSearch.roc

@@ -0,0 +1,8 @@
+module [search]
+
+Position : { column : U64, row : U64 }
+WordLocation : { start : Position, end : Position }
+
+search : Str, List Str -> Dict Str WordLocation
+search = \grid, wordsToSearchFor ->
+    crash "Please implement the 'search' function"