add armstrong-numbers

config.json

@@ -61,6 +61,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "armstrong-numbers",
+        "name": "Armstrong Numbers",
+        "uuid": "618bde52-73d2-4688-afd9-599f733ed05d",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "bob",
         "name": "Bob",

exercises/practice/armstrong-numbers/.docs/instructions.md

@@ -0,0 +1,14 @@
+# Instructions
+
+An [Armstrong number][armstrong-number] is a number that is the sum of its own digits each raised to the power of the number of digits.
+
+For example:
+
+- 9 is an Armstrong number, because `9 = 9^1 = 9`
+- 10 is _not_ an Armstrong number, because `10 != 1^2 + 0^2 = 1`
+- 153 is an Armstrong number, because: `153 = 1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153`
+- 154 is _not_ an Armstrong number, because: `154 != 1^3 + 5^3 + 4^3 = 1 + 125 + 64 = 190`
+
+Write some code to determine whether a number is an Armstrong number.
+
+[armstrong-number]: https://en.wikipedia.org/wiki/Narcissistic_number

exercises/practice/armstrong-numbers/.gitignore

@@ -0,0 +1,2 @@
+node_modules
+**/*.res.js

exercises/practice/armstrong-numbers/.meta/ArmstrongNumbers.res

@@ -0,0 +1,6 @@
+let isArmstrongNumber = n => {
+  let digits = n->Int.toString->String.split("")->Array.filterMap(d => d->Int.fromString)
+  let len = Array.length(digits)
+  let sum = Array.reduce(digits, 0, (acc, digit) => digit ** len + acc)
+  n == sum
+}

exercises/practice/armstrong-numbers/.meta/ArmstrongNumbers.resi

@@ -0,0 +1 @@
+let isArmstrongNumber: int => bool

exercises/practice/armstrong-numbers/.meta/config.json

@@ -0,0 +1,22 @@
+{
+  "authors": [
+    "tejasbubane",
+    "therealowenrees"
+  ],
+  "files": {
+    "solution": [
+      "src/ArmstrongNumbers.res",
+      "src/ArmstrongNumbers.resi"
+    ],
+    "test": [
+      "tests/ArmstrongNumbers_test.res"
+    ],
+    "example": [
+      ".meta/ArmstrongNumbers.res",
+      ".meta/ArmstrongNumbers.resi"
+    ]
+  },
+  "blurb": "Determine if a number is an Armstrong number.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Narcissistic_number"
+}

exercises/practice/armstrong-numbers/.meta/testTemplate.js

@@ -0,0 +1,17 @@
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import { assertEqual } from "../../../../test_generator/assertions.js";
+import { generateTests } from '../../../../test_generator/testGenerator.js';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+const slug = path.basename(path.resolve(__dirname, '..'))
+
+// EDIT THIS WITH YOUR ASSERTIONS
+export const assertionFunctions = [ assertEqual ]
+
+// EDIT THIS WITH YOUR TEST TEMPLATES
+export const template = (c) => {
+  return `assertEqual(~message="${c.description}", isArmstrongNumber(${c.input.number}), ${c.expected})`
+}
+
+generateTests(__dirname, slug, assertionFunctions, template)

exercises/practice/armstrong-numbers/.meta/tests.toml

@@ -0,0 +1,45 @@
+# 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.
+
+[c1ed103c-258d-45b2-be73-d8c6d9580c7b]
+description = "Zero is an Armstrong number"
+
+[579e8f03-9659-4b85-a1a2-d64350f6b17a]
+description = "Single-digit numbers are Armstrong numbers"
+
+[2d6db9dc-5bf8-4976-a90b-b2c2b9feba60]
+description = "There are no two-digit Armstrong numbers"
+
+[509c087f-e327-4113-a7d2-26a4e9d18283]
+description = "Three-digit number that is an Armstrong number"
+
+[7154547d-c2ce-468d-b214-4cb953b870cf]
+description = "Three-digit number that is not an Armstrong number"
+
+[6bac5b7b-42e9-4ecb-a8b0-4832229aa103]
+description = "Four-digit number that is an Armstrong number"
+
+[eed4b331-af80-45b5-a80b-19c9ea444b2e]
+description = "Four-digit number that is not an Armstrong number"
+
+[f971ced7-8d68-4758-aea1-d4194900b864]
+description = "Seven-digit number that is an Armstrong number"
+
+[7ee45d52-5d35-4fbd-b6f1-5c8cd8a67f18]
+description = "Seven-digit number that is not an Armstrong number"
+
+[5ee2fdf8-334e-4a46-bb8d-e5c19c02c148]
+description = "Armstrong number containing seven zeroes"
+include = false
+
+[12ffbf10-307a-434e-b4ad-c925680e1dd4]
+description = "The largest and last Armstrong number"
+include = false

exercises/practice/armstrong-numbers/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 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.