Add leap-year exercise

config.json

@@ -234,6 +234,14 @@
           "transforming"
         ]
       },
+      {
+        "slug": "leap",
+        "name": "Leap",
+        "uuid": "fed8614b-fa32-465e-8699-dbcf0cfc0798",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "linked-list",
         "name": "Linked List",

exercises/practice/leap/.docs/instructions.md

@@ -0,0 +1,22 @@
+# Instructions
+
+Given a year, report if it is a leap year.
+
+The tricky thing here is that a leap year in the Gregorian calendar occurs:
+
+```text
+on every year that is evenly divisible by 4
+  except every year that is evenly divisible by 100
+    unless the year is also evenly divisible by 400
+```
+
+For example, 1997 is not a leap year, but 1996 is.
+1900 is not a leap year, but 2000 is.
+
+## Notes
+
+Though our exercise adopts some very simple rules, there is more to learn!
+
+For a delightful, four minute explanation of the whole leap year phenomenon, go watch [this youtube video][video].
+
+[video]: https://www.youtube.com/watch?v=xX96xng7sAE

exercises/practice/leap/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "leap.coffee"
+    ],
+    "test": [
+      "leap.spec.coffee"
+    ],
+    "example": [
+      ".meta/example.coffee"
+    ]
+  },
+  "blurb": "Given a year, report if it is a leap year.",
+  "source": "CodeRanch Cattle Drive, Assignment 3",
+  "source_url": "https://coderanch.com/t/718816/Leap"
+}

exercises/practice/leap/.meta/example.coffee

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+class Leap
+  leapYear: (year) ->
+    year % 4 == 0 && (!(year % 100 == 0) || year % 400 == 0)
+module.exports = Leap

exercises/practice/leap/.meta/tests.toml

@@ -0,0 +1,37 @@
+# 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.
+
+[6466b30d-519c-438e-935d-388224ab5223]
+description = "year not divisible by 4 in common year"
+
+[ac227e82-ee82-4a09-9eb6-4f84331ffdb0]
+description = "year divisible by 2, not divisible by 4 in common year"
+
+[4fe9b84c-8e65-489e-970b-856d60b8b78e]
+description = "year divisible by 4, not divisible by 100 in leap year"
+
+[7fc6aed7-e63c-48f5-ae05-5fe182f60a5d]
+description = "year divisible by 4 and 5 is still a leap year"
+
+[78a7848f-9667-4192-ae53-87b30c9a02dd]
+description = "year divisible by 100, not divisible by 400 in common year"
+
+[9d70f938-537c-40a6-ba19-f50739ce8bac]
+description = "year divisible by 100 but not by 3 is still not a leap year"
+
+[42ee56ad-d3e6-48f1-8e3f-c84078d916fc]
+description = "year divisible by 400 is leap year"
+
+[57902c77-6fe9-40de-8302-587b5c27121e]
+description = "year divisible by 400 but not by 125 is still a leap year"
+
+[c30331f6-f9f6-4881-ad38-8ca8c12520c1]
+description = "year divisible by 200, not divisible by 400 in common year"

exercises/practice/leap/leap.coffee

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+class Leap
+  leapYear: (year) ->
+
+module.exports = Leap

exercises/practice/leap/leap.spec.coffee

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+Leap = require './leap'
+
+describe 'Leap', ->
+  leap = new Leap()
+  it 'year not divisible by 4 is common year', ->
+    result = leap.leapYear(2015)
+    expect(result).toEqual false
+
+  it 'year divisible by 2, not divisible by 4 is common year', ->
+    result = leap.leapYear(1970)
+    expect(result).toEqual false
+
+  it 'year divisible by 4, not divisible by 100 is leap year', ->
+    result = leap.leapYear(1996)
+    expect(result).toEqual true
+
+  it 'year divisible by 4 and 5 is still a leap year', ->
+    result = leap.leapYear(1960)
+    expect(result).toEqual true
+
+  it 'year divisible by 100, not divisible by 400 is common year', ->
+    result = leap.leapYear(2100)
+    expect(result).toEqual false
+
+  it 'year divisible by 100 but not by 3 is still not a leap year', ->
+    result = leap.leapYear 1900
+    expect(result).toEqual false
+
+  it 'year divisible by 400 is leap year', ->
+    result = leap.leapYear 2000 
+    expect(result).toEqual true
+
+  it 'year divisible by 400 but not by 125 is still a leap year', ->
+    result = leap.leapYear(2400)
+    expect(result).toEqual true
+
+  it 'year divisible by 200, not divisible by 400 is common year', ->
+    result = leap.leapYear(1800)
+    expect(result).toEqual false