Add dominoes exercise

config.json

@@ -551,6 +551,14 @@
         "prerequisites": [],
         "difficulty": 6
       },
+      {
+        "slug": "dominoes",
+        "name": "Dominoes",
+        "uuid": "9a60bba5-0ac4-4621-aa23-1e8e7dfe9d2b",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 6
+      },
       {
         "slug": "food-chain",
         "name": "Food Chain",

exercises/practice/dominoes/.docs/instructions.append.md

@@ -0,0 +1,11 @@
+# Instruction append
+
+## Input format
+
+Each domino is stored as two consecutive bytes in linear memory, one byte for each half.
+
+For example, stones `[2|1]`, `[2|3]` and `[1|3]` are represented as the byte array `[ 0x02, 0x01, 0x02, 0x03, 0x01, 0x03 ]`
+
+## Reserved Memory
+
+The buffer for the input dominoes uses bytes 256-511 of linear memory.

exercises/practice/dominoes/.docs/instructions.md

@@ -0,0 +1,15 @@
+# Instructions
+
+Make a chain of dominoes.
+
+Compute a way to order a given set of domino stones so that they form a correct domino chain.
+In the chain, the dots on one half of a stone must match the dots on the neighboring half of an adjacent stone.
+Additionally, the dots on the halves of the stones without neighbors (the first and last stone) must match each other.
+
+For example given the stones `[2|1]`, `[2|3]` and `[1|3]` you should compute something
+like `[1|2] [2|3] [3|1]` or `[3|2] [2|1] [1|3]` or `[1|3] [3|2] [2|1]` etc, where the first and last numbers are the same.
+
+For stones `[1|2]`, `[4|1]` and `[2|3]` the resulting chain is not valid: `[4|1] [1|2] [2|3]`'s first and last numbers are not the same.
+4 != 3
+
+Some test cases may use duplicate stones in a chain solution, assume that multiple Domino sets are being used.

exercises/practice/dominoes/.docs/introduction.md

@@ -0,0 +1,13 @@
+# Introduction
+
+In Toyland, the trains are always busy delivering treasures across the city, from shiny marbles to rare building blocks.
+The tracks they run on are made of colorful domino-shaped pieces, each marked with two numbers.
+For the trains to move, the dominoes must form a perfect chain where the numbers match.
+
+Today, an urgent delivery of rare toys is on hold.
+You've been handed a set of track pieces to inspect.
+If they can form a continuous chain, the train will be on its way, bringing smiles across Toyland.
+If not, the set will be discarded, and another will be tried.
+
+The toys are counting on you to solve this puzzle.
+Will the dominoes connect the tracks and send the train rolling, or will the set be left behind?

exercises/practice/dominoes/.eslintrc

@@ -0,0 +1,18 @@
+{
+  "root": true,
+  "extends": "@exercism/eslint-config-javascript",
+  "env": {
+    "jest": true
+  },
+  "overrides": [
+    {
+      "files": [
+        "*.spec.js"
+      ],
+      "excludedFiles": [
+        "custom.spec.js"
+      ],
+      "extends": "@exercism/eslint-config-javascript/maintainers"
+    }
+  ]
+}

exercises/practice/dominoes/.meta/config.json

@@ -0,0 +1,26 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "dominoes.wat"
+    ],
+    "test": [
+      "dominoes.spec.js"
+    ],
+    "example": [
+      ".meta/proof.ci.wat"
+    ],
+    "invalidator": [
+      "package.json"
+    ]
+  },
+  "blurb": "Make a chain of dominoes.",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
+}

exercises/practice/dominoes/.meta/proof.ci.wat

@@ -0,0 +1,118 @@
+(module
+  (memory (export "mem") 1)
+
+  (global $parentTable i32 (i32.const 0))
+
+  (global $tallyTable i32 (i32.const 32))
+
+  (func $root (param $nibble i32) (result i32)
+    (local $current i32)
+    (local $parent i32)
+    (local.set $parent (local.get $nibble))
+
+    (loop $traverse
+      (local.set $current (local.get $parent))
+      (local.set $parent (i32.load8_u (i32.add (global.get $parentTable)
+                                               (local.get $current))))
+      (br_if $traverse (i32.ne (local.get $parent)
+                               (local.get $current)))
+    )
+
+    (return (local.get $current))
+  )
+
+  (func $updateTally (param $value i32)
+    (local $ptr i32)
+
+    (local.set $ptr (i32.add (global.get $tallyTable)
+                             (local.get $value)))
+    (i32.store8 (local.get $ptr)
+                (i32.add (i32.const 1)
+                         (i32.load8_u (local.get $ptr))))
+  )
+
+  ;;
+  ;; Determine if the dominoes form a chain.
+  ;;
+  ;; Each domino is stored as two consecutive bytes in linear memory (left, right).
+  ;;
+  ;; @param {i32} offset - offset of domino array in linear memory
+  ;; @param {i32} count  - number of dominoes
+  ;;
+  ;; @returns {i32} 1 if the dominoes form a chain, 0 otherwise
+  ;;
+  (func (export "canChain") (param $offset i32) (param $count i32) (result i32)
+    (local $i i32)
+    (local $left i32)
+    (local $right i32)
+    (local $roots i32)
+    (local $tally i32)
+
+    (if (i32.eqz (local.get $count)) (then
+      (return (i32.const 1))
+    ))
+
+    (memory.fill (global.get $tallyTable) (i32.const 0) (i32.const 32))
+
+    (local.set $i (i32.const 0))
+    (loop $init
+      (i32.store8 (i32.add (global.get $parentTable)
+                           (local.get $i))
+                  (local.get $i))
+      (local.set $i (i32.add (local.get $i)
+                             (i32.const 1)))
+      (br_if $init (i32.lt_u (local.get $i)
+                             (i32.const 32)))
+    )
+
+    (loop $read
+      (local.set $left (i32.load8_u (local.get $offset)))
+      (local.set $right (i32.load8_u (i32.add (local.get $offset)
+                                              (i32.const 1))))
+      (local.set $offset (i32.add (local.get $offset)
+                                  (i32.const 2)))
+      (local.set $count (i32.sub (local.get $count)
+                                 (i32.const 1)))
+
+      (call $updateTally (local.get $left))
+      (call $updateTally (local.get $right))
+
+      (local.set $left (call $root (local.get $left)))
+      (local.set $right (call $root (local.get $right)))
+
+      (i32.store8 (i32.add (global.get $parentTable)
+                           (local.get $left))
+                  (local.get $right))
+
+      (br_if $read (local.get $count))
+    )
+
+    (local.set $roots (i32.const 0))
+    (local.set $i (i32.const 0))
+    (loop $count_roots
+      (local.set $tally (i32.load8_u (i32.add (global.get $tallyTable)
+                                              (local.get $i))))
+      (if (local.get $tally) (then
+        (if (i32.and (local.get $tally)
+                     (i32.const 1)) (then
+          (return (i32.const 0)
+        )))
+
+        (if (i32.eq (local.get $i)
+                    (i32.load8_u (i32.add (global.get $parentTable)
+                                          (local.get $i)))) (then
+          (local.set $roots (i32.add (local.get $roots)
+                                     (i32.const 1)))
+        ))
+      ))
+
+      (local.set $i (i32.add (local.get $i)
+                             (i32.const 1)))
+      (br_if $count_roots (i32.lt_u (local.get $i)
+                              (i32.const 32)))
+    )
+
+    (return (i32.eq (local.get $roots)
+                    (i32.const 1)))
+  )
+)

exercises/practice/dominoes/.meta/tests.toml

@@ -0,0 +1,49 @@
+# 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.
+
+[31a673f2-5e54-49fe-bd79-1c1dae476c9c]
+description = "empty input = empty output"
+
+[4f99b933-367b-404b-8c6d-36d5923ee476]
+description = "singleton input = singleton output"
+
+[91122d10-5ec7-47cb-b759-033756375869]
+description = "singleton that can't be chained"
+
+[be8bc26b-fd3d-440b-8e9f-d698a0623be3]
+description = "three elements"
+
+[99e615c6-c059-401c-9e87-ad7af11fea5c]
+description = "can reverse dominoes"
+
+[51f0c291-5d43-40c5-b316-0429069528c9]
+description = "can't be chained"
+
+[9a75e078-a025-4c23-8c3a-238553657f39]
+description = "disconnected - simple"
+
+[0da0c7fe-d492-445d-b9ef-1f111f07a301]
+description = "disconnected - double loop"
+
+[b6087ff0-f555-4ea0-a71c-f9d707c5994a]
+description = "disconnected - single isolated"
+
+[2174fbdc-8b48-4bac-9914-8090d06ef978]
+description = "need backtrack"
+
+[167bb480-dfd1-4318-a20d-4f90adb4a09f]
+description = "separate loops"
+
+[cd061538-6046-45a7-ace9-6708fe8f6504]
+description = "nine elements"
+
+[44704c7c-3adb-4d98-bd30-f45527cf8b49]
+description = "separate three-domino loops"

exercises/practice/dominoes/.npmrc

@@ -0,0 +1 @@
+audit=false

exercises/practice/dominoes/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

exercises/practice/dominoes/babel.config.js

@@ -0,0 +1,4 @@
+export default {
+  presets: ["@exercism/babel-preset-javascript"],
+  plugins: [],
+};