add yacht exercise

config.json

@@ -1201,6 +1201,15 @@
         "prerequisites": [],
         "difficulty": 9,
         "topics": ["algorithms"]
+      },
+      {
+        "slug": "yacht",
+        "name": "Yacht",
+        "uuid": "06ac7eed-1417-4510-b526-eb068af21ad9",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4,
+        "topics": ["arrays", "conditionals", "filtering", "games"]
       }
     ]
   },

exercises/practice/yacht/.docs/instructions.md

@@ -0,0 +1,35 @@
+# Instructions
+
+The dice game [Yacht][yacht] is from the same family as Poker Dice, Generala and particularly Yahtzee, of which it is a precursor.
+In the game, five dice are rolled and the result can be entered in any of twelve categories.
+The score of a throw of the dice depends on category chosen.
+
+## Scores in Yacht
+
+| Category        | Score                  | Description                              | Example             |
+| --------------- | ---------------------- | ---------------------------------------- | ------------------- |
+| Ones            | 1 × number of ones     | Any combination                          | 1 1 1 4 5 scores 3  |
+| Twos            | 2 × number of twos     | Any combination                          | 2 2 3 4 5 scores 4  |
+| Threes          | 3 × number of threes   | Any combination                          | 3 3 3 3 3 scores 15 |
+| Fours           | 4 × number of fours    | Any combination                          | 1 2 3 3 5 scores 0  |
+| Fives           | 5 × number of fives    | Any combination                          | 5 1 5 2 5 scores 15 |
+| Sixes           | 6 × number of sixes    | Any combination                          | 2 3 4 5 6 scores 6  |
+| Full House      | Total of the dice      | Three of one number and two of another   | 3 3 3 5 5 scores 19 |
+| Four of a Kind  | Total of the four dice | At least four dice showing the same face | 4 4 4 4 6 scores 16 |
+| Little Straight | 30 points              | 1-2-3-4-5                                | 1 2 3 4 5 scores 30 |
+| Big Straight    | 30 points              | 2-3-4-5-6                                | 2 3 4 5 6 scores 30 |
+| Choice          | Sum of the dice        | Any combination                          | 2 3 3 4 6 scores 18 |
+| Yacht           | 50 points              | All five dice showing the same face      | 4 4 4 4 4 scores 50 |
+
+If the dice do not satisfy the requirements of a category, the score is zero.
+If, for example, _Four Of A Kind_ is entered in the _Yacht_ category, zero points are scored.
+A _Yacht_ scores zero if entered in the _Full House_ category.
+
+## Task
+
+Given a list of values for five dice and a category, your solution should return the score of the dice for that category.
+If the dice do not satisfy the requirements of the category your solution should return 0.
+You can assume that five values will always be presented, and the value of each will be between one and six inclusively.
+You should not assume that the dice are ordered.
+
+[yacht]: https://en.wikipedia.org/wiki/Yacht_(dice_game)

exercises/practice/yacht/.eslintignore

@@ -0,0 +1,13 @@
+!.meta
+
+# Protected or generated
+.git
+.vscode
+
+# When using npm
+node_modules/*
+
+# Configuration files
+.eslintrc.cjs
+babel.config.cjs
+jest.config.cjs

exercises/practice/yacht/.eslintrc.cjs

@@ -0,0 +1,38 @@
+module.exports = {
+  root: true,
+  parserOptions: {
+    tsconfigRootDir: __dirname,
+    project: ['./tsconfig.json'],
+  },
+  overrides: [
+    // Student provided files
+    {
+      files: ['*.ts'],
+      excludedFiles: ['.meta/proof.ci.ts', '.meta/exemplar.ts', '*.test.ts'],
+      extends: '@exercism/eslint-config-typescript',
+    },
+    // Exercism given tests
+    {
+      files: ['*.test.ts'],
+      excludedFiles: ['custom.test.ts'],
+      env: {
+        jest: true,
+      },
+      extends: '@exercism/eslint-config-typescript/maintainers',
+    },
+    // Student provided tests
+    {
+      files: ['custom.test.ts'],
+      env: {
+        jest: true,
+      },
+      extends: '@exercism/eslint-config-typescript',
+    },
+    // Exercism provided files
+    {
+      files: ['.meta/proof.ci.ts', '.meta/exemplar.ts', '*.test.ts'],
+      excludedFiles: ['custom.test.ts'],
+      extends: '@exercism/eslint-config-typescript/maintainers',
+    },
+  ],
+}

exercises/practice/yacht/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "xavdid"
+  ],
+  "files": {
+    "solution": [
+      "yacht.ts"
+    ],
+    "test": [
+      "yacht.test.ts"
+    ],
+    "example": [
+      ".meta/proof.ci.ts"
+    ]
+  },
+  "blurb": "Score a single throw of dice in the game Yacht.",
+  "source": "James Kilfiger, using wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Yacht_(dice_game)"
+}

exercises/practice/yacht/.meta/proof.ci.ts

@@ -0,0 +1,85 @@
+export const enum Category {
+  ONES,
+  TWOS,
+  THREES,
+  FOURS,
+  FIVES,
+  SIXES,
+  FULL_HOUSE,
+  FOUR_OF_A_KIND,
+  LITTLE_STRAIGHT,
+  BIG_STRAIGHT,
+  CHOICE,
+  YACHT,
+}
+
+/**
+ * multiplies the number of occurances of a specific value by that number
+ */
+const countSingles = (dice: number[], value: number): number =>
+  value * dice.filter((d) => d === value).length
+
+/**
+ * sorts a list of numbers in numerically increasing order
+ */
+const sortNumbers = (dice: number[]): number[] => dice.toSorted((a, b) => a - b)
+
+/**
+ * build a mapping of the number of occurances of each die. For example. a full house of 1s and 6s will return `{1: 2, 6: 3}`
+ */
+const frequencies = (dice: number[]): Record<string, number> =>
+  dice.reduce(
+    (res, d) => ({
+      ...res,
+      [d]: (res[d] ?? 0) + 1,
+    }),
+    {} as Record<string, number>
+  )
+
+/**
+ * sums a list of numbers
+ */
+const sum = (dice: number[]): number => dice.reduce((res, d) => d + res, 0)
+
+/**
+ * compares two list of numbers for equality
+ */
+const eq = (l: number[], r: number[]): boolean =>
+  JSON.stringify(l) === JSON.stringify(r)
+
+export const score = (dice: number[], category: Category): number => {
+  switch (category) {
+    case Category.ONES:
+      return countSingles(dice, 1)
+    case Category.TWOS:
+      return countSingles(dice, 2)
+    case Category.THREES:
+      return countSingles(dice, 3)
+    case Category.FOURS:
+      return countSingles(dice, 4)
+    case Category.FIVES:
+      return countSingles(dice, 5)
+    case Category.SIXES:
+      return countSingles(dice, 6)
+    case Category.FULL_HOUSE:
+      return eq(sortNumbers(Object.values(frequencies(dice))), [2, 3])
+        ? sum(dice)
+        : 0
+    case Category.FOUR_OF_A_KIND:
+      return sum(
+        Object.entries(frequencies(dice)).map(([d, count]) =>
+          count >= 4 ? parseInt(d) * 4 : 0
+        )
+      )
+    case Category.LITTLE_STRAIGHT:
+      return eq(sortNumbers(dice), [1, 2, 3, 4, 5]) ? 30 : 0
+    case Category.BIG_STRAIGHT:
+      return eq(sortNumbers(dice), [2, 3, 4, 5, 6]) ? 30 : 0
+    case Category.CHOICE:
+      return sum(dice)
+    case Category.YACHT:
+      return new Set(dice).size === 1 ? 50 : 0
+    default:
+      throw new Error(`unhandled case: ${category}`)
+  }
+}

exercises/practice/yacht/.meta/tests.toml

@@ -0,0 +1,97 @@
+# 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.
+
+[3060e4a5-4063-4deb-a380-a630b43a84b6]
+description = "Yacht"
+
+[15026df2-f567-482f-b4d5-5297d57769d9]
+description = "Not Yacht"
+
+[36b6af0c-ca06-4666-97de-5d31213957a4]
+description = "Ones"
+
+[023a07c8-6c6e-44d0-bc17-efc5e1b8205a]
+description = "Ones, out of order"
+
+[7189afac-cccd-4a74-8182-1cb1f374e496]
+description = "No ones"
+
+[793c4292-dd14-49c4-9707-6d9c56cee725]
+description = "Twos"
+
+[dc41bceb-d0c5-4634-a734-c01b4233a0c6]
+description = "Fours"
+
+[f6125417-5c8a-4bca-bc5b-b4b76d0d28c8]
+description = "Yacht counted as threes"
+
+[464fc809-96ed-46e4-acb8-d44e302e9726]
+description = "Yacht of 3s counted as fives"
+
+[d054227f-3a71-4565-a684-5c7e621ec1e9]
+description = "Fives"
+
+[e8a036e0-9d21-443a-8b5f-e15a9e19a761]
+description = "Sixes"
+
+[51cb26db-6b24-49af-a9ff-12f53b252eea]
+description = "Full house two small, three big"
+
+[1822ca9d-f235-4447-b430-2e8cfc448f0c]
+description = "Full house three small, two big"
+
+[b208a3fc-db2e-4363-a936-9e9a71e69c07]
+description = "Two pair is not a full house"
+
+[b90209c3-5956-445b-8a0b-0ac8b906b1c2]
+description = "Four of a kind is not a full house"
+
+[32a3f4ee-9142-4edf-ba70-6c0f96eb4b0c]
+description = "Yacht is not a full house"
+
+[b286084d-0568-4460-844a-ba79d71d79c6]
+description = "Four of a Kind"
+
+[f25c0c90-5397-4732-9779-b1e9b5f612ca]
+description = "Yacht can be scored as Four of a Kind"
+
+[9f8ef4f0-72bb-401a-a871-cbad39c9cb08]
+description = "Full house is not Four of a Kind"
+
+[b4743c82-1eb8-4a65-98f7-33ad126905cd]
+description = "Little Straight"
+
+[7ac08422-41bf-459c-8187-a38a12d080bc]
+description = "Little Straight as Big Straight"
+
+[97bde8f7-9058-43ea-9de7-0bc3ed6d3002]
+description = "Four in order but not a little straight"
+
+[cef35ff9-9c5e-4fd2-ae95-6e4af5e95a99]
+description = "No pairs but not a little straight"
+
+[fd785ad2-c060-4e45-81c6-ea2bbb781b9d]
+description = "Minimum is 1, maximum is 5, but not a little straight"
+
+[35bd74a6-5cf6-431a-97a3-4f713663f467]
+description = "Big Straight"
+
+[87c67e1e-3e87-4f3a-a9b1-62927822b250]
+description = "Big Straight as little straight"
+
+[c1fa0a3a-40ba-4153-a42d-32bc34d2521e]
+description = "No pairs but not a big straight"
+
+[207e7300-5d10-43e5-afdd-213e3ac8827d]
+description = "Choice"
+
+[b524c0cf-32d2-4b40-8fb3-be3500f3f135]
+description = "Yacht as choice"