Added the perfect-numbers exercise

config.json

@@ -146,6 +146,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 1
+      },
+      {
+        "slug": "perfect-numbers",
+        "name": "Perfect Numbers",
+        "uuid": "ab9aa9bd-c6a1-4989-a1a5-b761818f38a3",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ]
   },

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

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+# Instructions
+
+Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for positive integers.
+
+The Greek mathematician [Nicomachus][nicomachus] devised a classification scheme for positive integers, identifying each as belonging uniquely to the categories of [perfect](#perfect), [abundant](#abundant), or [deficient](#deficient) based on their [aliquot sum][aliquot-sum].
+The _aliquot sum_ is defined as the sum of the factors of a number not including the number itself.
+For example, the aliquot sum of `15` is `1 + 3 + 5 = 9`.
+
+## Perfect
+
+A number is perfect when it equals its aliquot sum.
+For example:
+
+- `6` is a perfect number because `1 + 2 + 3 = 6`
+- `28` is a perfect number because `1 + 2 + 4 + 7 + 14 = 28`
+
+## Abundant
+
+A number is abundant when it is less than its aliquot sum.
+For example:
+
+- `12` is an abundant number because `1 + 2 + 3 + 4 + 6 = 16`
+- `24` is an abundant number because `1 + 2 + 3 + 4 + 6 + 8 + 12 = 36`
+
+## Deficient
+
+A number is deficient when it is greater than its aliquot sum.
+For example:
+
+- `8` is a deficient number because `1 + 2 + 4 = 7`
+- Prime numbers are deficient
+
+## Task
+
+Implement a way to determine whether a given number is [perfect](#perfect).
+Depending on your language track, you may also need to implement a way to determine whether a given number is [abundant](#abundant) or [deficient](#deficient).
+
+[nicomachus]: https://en.wikipedia.org/wiki/Nicomachus
+[aliquot-sum]: https://en.wikipedia.org/wiki/Aliquot_sum

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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "gvrooyen"
+  ],
+  "files": {
+    "solution": [
+      "perfect_numbers.odin"
+    ],
+    "test": [
+      "perfect_numbers_test.odin"
+    ],
+    "example": [
+      ".meta/perfect_numbers_example.odin"
+    ]
+  },
+  "blurb": "Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for positive integers.",
+  "source": "Taken from Chapter 2 of Functional Thinking by Neal Ford.",
+  "source_url": "https://www.oreilly.com/library/view/functional-thinking/9781449365509/"
+}

exercises/practice/perfect-numbers/.meta/perfect_numbers_example.odin

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+package perfect_numbers
+
+import "core:math"
+
+Classification :: enum {
+	Perfect,
+	Abundant,
+	Deficient,
+	Undefined,
+}
+
+// Returns the sum of the divisors of `number` (excluding `number` itself).
+// For example, the aliquot sum of 15 is (1 + 3 + 5) = 9
+aliquot_sum :: proc(number: uint) -> uint {
+	if number <= 1 do return 0
+	result: uint = 1
+	for i in 2 ..= (number / 2) {
+		if number % i == 0 do result += i
+	}
+	return result
+}
+
+// Returns whether `number` is less than, equal to, or greater than its aliquot sum.
+// `ok` will be false if invalid input (i.e. 0) is provided.
+classify :: proc(number: uint) -> Classification {
+	using Classification
+	if number == 0 do return Undefined
+	sum := aliquot_sum(number)
+	switch {
+	case number < sum:
+		return Abundant
+	case number > sum:
+		return Deficient
+	case:
+		return Perfect
+	}
+}

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

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+# 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.
+
+[163e8e86-7bfd-4ee2-bd68-d083dc3381a3]
+description = "Perfect numbers -> Smallest perfect number is classified correctly"
+
+[169a7854-0431-4ae0-9815-c3b6d967436d]
+description = "Perfect numbers -> Medium perfect number is classified correctly"
+
+[ee3627c4-7b36-4245-ba7c-8727d585f402]
+description = "Perfect numbers -> Large perfect number is classified correctly"
+
+[80ef7cf8-9ea8-49b9-8b2d-d9cb3db3ed7e]
+description = "Abundant numbers -> Smallest abundant number is classified correctly"
+
+[3e300e0d-1a12-4f11-8c48-d1027165ab60]
+description = "Abundant numbers -> Medium abundant number is classified correctly"
+
+[ec7792e6-8786-449c-b005-ce6dd89a772b]
+description = "Abundant numbers -> Large abundant number is classified correctly"
+
+[e610fdc7-2b6e-43c3-a51c-b70fb37413ba]
+description = "Deficient numbers -> Smallest prime deficient number is classified correctly"
+
+[0beb7f66-753a-443f-8075-ad7fbd9018f3]
+description = "Deficient numbers -> Smallest non-prime deficient number is classified correctly"
+
+[1c802e45-b4c6-4962-93d7-1cad245821ef]
+description = "Deficient numbers -> Medium deficient number is classified correctly"
+
+[47dd569f-9e5a-4a11-9a47-a4e91c8c28aa]
+description = "Deficient numbers -> Large deficient number is classified correctly"
+
+[a696dec8-6147-4d68-afad-d38de5476a56]
+description = "Deficient numbers -> Edge case (no factors other than itself) is classified correctly"
+
+[72445cee-660c-4d75-8506-6c40089dc302]
+description = "Invalid inputs -> Zero is rejected (as it is not a positive integer)"
+
+[2d72ce2c-6802-49ac-8ece-c790ba3dae13]
+description = "Invalid inputs -> Negative integer is rejected (as it is not a positive integer)"

exercises/practice/perfect-numbers/perfect_numbers.odin

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+package perfect_numbers
+
+Classification :: enum {
+	Perfect,
+	Abundant,
+	Deficient,
+	Undefined,
+}
+
+classify :: proc(number: uint) -> Classification {
+	#panic("Please implement the `classify` procedure.")
+}

exercises/practice/perfect-numbers/perfect_numbers_test.odin

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+/* These are the unit tests for the exercise. Only the first one is enabled to start with. You can
+ * enable the other tests by uncommenting the `@(test)` attribute of the test procedure. Your
+ * solution should pass all tests before it is ready for submission.
+ */
+
+package perfect_numbers
+
+import "core:testing"
+
+@(test)
+test_smallest_perfect_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(6), Classification.Perfect)
+}
+
+// @(test)
+test_medium_perfect_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(28), Classification.Perfect)
+}
+
+// @(test)
+test_large_perfect_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(33550336), Classification.Perfect)
+}
+
+// @(test)
+test_smallest_abundant_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(12), Classification.Abundant)
+}
+
+// @(test)
+test_medium_abundant_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(30), Classification.Abundant)
+}
+
+// @(test)
+test_large_abundant_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(33550335), Classification.Abundant)
+}
+
+// @(test)
+test_smallest_prime_deficient_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(2), Classification.Deficient)
+}
+
+// @(test)
+test_smallest_non_prime_deficient_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(4), Classification.Deficient)
+}
+
+// @(test)
+test_medium_deficient_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(32), Classification.Deficient)
+}
+
+// @(test)
+test_large_deficient_number :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(33550337), Classification.Deficient)
+}
+
+// @(test)
+test_1_is_edge_case :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(1), Classification.Deficient)
+}
+
+// @(test)
+test_zero_is_undefined :: proc(t: ^testing.T) {
+	testing.expect_value(t, classify(0), Classification.Undefined)
+}