Add practice exercise: perfect-numbers

config.json

@@ -234,6 +234,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "perfect-numbers",
+        "name": "Perfect Numbers",
+        "uuid": "309666ba-cbde-429b-ae07-ddb05366bf0a",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "resistor-color-trio",
         "name": "Resistor Color Trio",
@@ -421,7 +429,7 @@
       {
         "slug": "run-length-encoding",
         "name": "Run-Length Encoding",
-        "uuid": "065feae7-f6fc-46b9-a226-d3d9df9d192b",  
+        "uuid": "065feae7-f6fc-46b9-a226-d3d9df9d192b",
         "practices": [],
         "prerequisites": [],
         "difficulty": 8

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

@@ -0,0 +1,39 @@
+# 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": [
+    "jimmytty"
+  ],
+  "files": {
+    "solution": [
+      "perfect-numbers.sql"
+    ],
+    "test": [
+      "perfect-numbers_test.sql"
+    ],
+    "example": [
+      ".meta/example.sql"
+    ]
+  },
+  "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/example.sql

@@ -0,0 +1,31 @@
+UPDATE "perfect-numbers"
+   SET error = 'Classification is only possible for positive integers.'
+ WHERE number < 1
+;
+
+UPDATE "perfect-numbers"
+   SET result = 'deficient'
+ WHERE number = 1
+   AND error ISNULL
+;
+
+UPDATE "perfect-numbers"
+   SET result = (
+       WITH
+         factors AS (
+           SELECT IIF(number % value = 0, value, 0) divisor
+             FROM GENERATE_SERIES(1, number / 2)),
+         aliquot_sums AS (
+           SELECT SUM(divisor) aliquot_sum
+             FROM factors
+         )
+       SELECT CASE
+              WHEN number = aliquot_sum THEN 'perfect'
+              WHEN number < aliquot_sum THEN 'abundant'
+              WHEN number > aliquot_sum THEN 'deficient'
+              END
+         FROM aliquot_sums
+       )
+ WHERE error  ISNULL
+   AND result ISNULL
+;

exercises/practice/perfect-numbers/.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.
+
+[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/create_fixture.sql

@@ -0,0 +1,11 @@
+DROP TABLE IF EXISTS "perfect-numbers";
+CREATE TABLE "perfect-numbers" (
+  number INTEGER NOT NULL,
+  result TEXT,
+  error  TEXT
+);
+
+.mode csv
+.import ./data.csv "perfect-numbers"
+
+UPDATE "perfect-numbers" SET result = NULL, error = NULL;

exercises/practice/perfect-numbers/create_test_table.sql

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+DROP TABLE IF EXISTS tests;
+CREATE TABLE IF NOT EXISTS tests (
+  -- uuid and description are taken from the test.toml file
+  uuid TEXT PRIMARY KEY,
+  description TEXT NOT NULL,
+  -- The following section is needed by the online test-runner
+  status TEXT DEFAULT 'fail',
+  message TEXT,
+  output TEXT,
+  test_code TEXT,
+  task_id INTEGER DEFAULT NULL,
+  -- Here are columns for the actual tests
+  number INTEGER NOT NULL,
+  expected_result TEXT,
+  expected_error TEXT
+);
+
+INSERT INTO tests (uuid, description, number, expected_result, expected_error)
+VALUES
+        ('163e8e86-7bfd-4ee2-bd68-d083dc3381a3', 'Smallest perfect number is classified correctly', 6, 'perfect', NULL),
+        ('169a7854-0431-4ae0-9815-c3b6d967436d', 'Medium perfect number is classified correctly', 28, 'perfect', NULL),
+        ('ee3627c4-7b36-4245-ba7c-8727d585f402', 'Large perfect number is classified correctly', 33550336, 'perfect', NULL),
+        ('80ef7cf8-9ea8-49b9-8b2d-d9cb3db3ed7e', 'Smallest abundant number is classified correctly', 12, 'abundant', NULL),
+        ('3e300e0d-1a12-4f11-8c48-d1027165ab60', 'Medium abundant number is classified correctly', 30, 'abundant', NULL),
+        ('ec7792e6-8786-449c-b005-ce6dd89a772b', 'Large abundant number is classified correctly', 33550335, 'abundant', NULL),
+        ('e610fdc7-2b6e-43c3-a51c-b70fb37413ba', 'Smallest prime deficient number is classified correctly', 2, 'deficient', NULL),
+        ('0beb7f66-753a-443f-8075-ad7fbd9018f3', 'Smallest non-prime deficient number is classified correctly', 4, 'deficient', NULL),
+        ('1c802e45-b4c6-4962-93d7-1cad245821ef', 'Medium deficient number is classified correctly', 32, 'deficient', NULL),
+        ('47dd569f-9e5a-4a11-9a47-a4e91c8c28aa', 'Large deficient number is classified correctly', 33550337, 'deficient', NULL),
+        ('a696dec8-6147-4d68-afad-d38de5476a56', 'Edge case (no factors other than itself) is classified correctly', 1, 'deficient', NULL),
+        ('72445cee-660c-4d75-8506-6c40089dc302', 'Zero is rejected (as it is not a positive integer)', 0, NULL, 'Classification is only possible for positive integers.'),
+        ('2d72ce2c-6802-49ac-8ece-c790ba3dae13', 'Negative integer is rejected (as it is not a positive integer)', -1, NULL, 'Classification is only possible for positive integers.');

exercises/practice/perfect-numbers/data.csv

@@ -0,0 +1,13 @@
+6,,
+28,,
+33550336,,
+12,,
+30,,
+33550335,,
+2,,
+4,,
+32,,
+33550337,,
+1,,
+0,,
+-1,,

exercises/practice/perfect-numbers/perfect-numbers.sql

@@ -0,0 +1,8 @@
+-- Schema:
+-- CREATE TABLE "perfect-numbers" (
+--   number INTEGER NOT NULL,
+--   result TEXT,
+--   error  TEXT
+-- );
+--
+-- Task: update the perfect-numbers table and set the result or the error columns based on number.

exercises/practice/perfect-numbers/perfect-numbers_test.sql

@@ -0,0 +1,48 @@
+-- Create database:
+.read ./create_fixture.sql
+
+-- Read user student solution and save any output as markdown in user_output.md:
+.mode markdown
+.output user_output.md
+.read ./perfect-numbers.sql
+.output
+
+-- Create a clean testing environment:
+.read ./create_test_table.sql
+
+-- Comparison of user input and the tests updates the status for each test:
+UPDATE tests
+   SET status = 'pass'
+  FROM (SELECT number, result, error FROM "perfect-numbers") AS actual
+ WHERE actual.number = tests.NUMBER
+   AND (actual.result = tests.expected_result
+        OR COALESCE(actual.result, tests.expected_result) ISNULL)
+   AND (actual.error = tests.expected_error
+        OR COALESCE(actual.error, tests.expected_error) ISNULL);
+
+-- Update message for failed tests to give helpful information:
+UPDATE tests
+   SET message = (
+         'Result for "' || actual.number || '"' || ' is <'
+         || PRINTF('result=%s and error=%s',
+                   COALESCE(actual.result, 'NULL'),
+                   COALESCE(actual.error, 'NULL'))
+         || '> but should be <'
+         || PRINTF('result=%s and error=%s',
+                   COALESCE(tests.expected_result, 'NULL'),
+                   COALESCE(tests.expected_error, 'NULL'))
+         || '>'
+       )
+  FROM (SELECT number, result, error FROM "perfect-numbers") AS actual
+ WHERE actual.number = tests.number AND tests.status = 'fail';
+
+-- Save results to ./output.json (needed by the online test-runner)
+.mode json
+.once './output.json'
+SELECT description, status, message, output, test_code, task_id
+FROM tests;
+
+-- Display test results in readable form for the student:
+.mode table
+SELECT description, status, message
+FROM tests;