Add series exercise (#375)

* Add series exercise

* reformat

config.json

@@ -465,6 +465,17 @@
           "math"
         ]
       },
+      {
+        "slug": "series",
+        "name": "Series",
+        "uuid": "2e10ca92-6232-418e-b9ea-506ac1eba195",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3,
+        "topics": [
+          "strings"
+        ]
+      },
       {
         "slug": "largest-series-product",
         "name": "Largest Series Product",

exercises/practice/series/.docs/instructions.md

@@ -0,0 +1,19 @@
+# Instructions
+
+Given a string of digits, output all the contiguous substrings of length `n` in that string in the order that they appear.
+
+For example, the string "49142" has the following 3-digit series:
+
+- "491"
+- "914"
+- "142"
+
+And the following 4-digit series:
+
+- "4914"
+- "9142"
+
+And if you ask for a 6-digit series from a 5-digit string, you deserve whatever you get.
+
+Note that these series are only required to occupy _adjacent positions_ in the input;
+the digits need not be _numerically consecutive_.

exercises/practice/series/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "series.el"
+    ],
+    "test": [
+      "series-test.el"
+    ],
+    "example": [
+      ".meta/example.el"
+    ]
+  },
+  "blurb": "Given a string of digits, output all the contiguous substrings of length `n` in that string.",
+  "source": "A subset of the Problem 8 at Project Euler",
+  "source_url": "https://projecteuler.net/problem=8"
+}

exercises/practice/series/.meta/example.el

@@ -0,0 +1,22 @@
+;;; series.el --- Series (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+
+(defun slices (series slice-length)
+  (cond
+    ((equal "" series) (error "series cannot be empty"))
+    ((> slice-length (length series)) (error "slice length cannot be greater than series length"))
+    ((= slice-length 0) (error "slice length cannot be zero"))
+    ((< slice-length 0) (error "slice length cannot be negative"))
+    (t (mapcar (lambda (start)
+                       (substring series start (+ start slice-length)))
+               (number-sequence 0 (- (length series) slice-length))))))
+
+
+(provide 'series)
+;;; series.el ends here
+

exercises/practice/series/.meta/tests.toml

@@ -0,0 +1,43 @@
+# 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.
+
+[7ae7a46a-d992-4c2a-9c15-a112d125ebad]
+description = "slices of one from one"
+
+[3143b71d-f6a5-4221-aeae-619f906244d2]
+description = "slices of one from two"
+
+[dbb68ff5-76c5-4ccd-895a-93dbec6d5805]
+description = "slices of two"
+
+[19bbea47-c987-4e11-a7d1-e103442adf86]
+description = "slices of two overlap"
+
+[8e17148d-ba0a-4007-a07f-d7f87015d84c]
+description = "slices can include duplicates"
+
+[bd5b085e-f612-4f81-97a8-6314258278b0]
+description = "slices of a long series"
+
+[6d235d85-46cf-4fae-9955-14b6efef27cd]
+description = "slice length is too large"
+
+[d7957455-346d-4e47-8e4b-87ed1564c6d7]
+description = "slice length is way too large"
+
+[d34004ad-8765-4c09-8ba1-ada8ce776806]
+description = "slice length cannot be zero"
+
+[10ab822d-8410-470a-a85d-23fbeb549e54]
+description = "slice length cannot be negative"
+
+[c7ed0812-0e4b-4bf3-99c4-28cbbfc246a2]
+description = "empty series is invalid"

exercises/practice/series/series-test.el

@@ -0,0 +1,64 @@
+;;; series-test.el --- Tests for Series (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+(load-file "series.el")
+(declare-function slices "series.el" (series slice-length))
+
+
+(ert-deftest slices-of-one-from-one ()
+  (should (equal '("1") (slices "1" 1))))
+
+
+(ert-deftest slices-of-one-from-two ()
+  (should (equal '("1" "2") (slices "12" 1))))
+
+
+(ert-deftest slices-of-two ()
+  (should (equal '("35") (slices "35" 2))))
+
+
+(ert-deftest slices-of-two-overlap ()
+  (should (equal '("91" "14" "42") (slices "9142" 2))))
+
+
+(ert-deftest slices-can-include-duplicates ()
+  (should (equal '("777" "777" "777" "777") (slices "777777" 3))))
+
+
+(ert-deftest slices-of-a-long-series ()
+  (should (equal '("91849"
+                   "18493"
+                   "84939"
+                   "49390"
+                   "93904"
+                   "39042"
+                   "90424"
+                   "04243")
+                 (slices "918493904243" 5))))
+
+
+(ert-deftest slice-length-is-too-large ()
+  (should-error (slices "12345" 6)))
+
+
+(ert-deftest slice-length-is-way-too-large ()
+  (should-error (slices "12345" 42)))
+
+
+(ert-deftest slice-length-cannot-be-zero ()
+  (should-error (slices "12345" 0)))
+
+
+(ert-deftest slice-length-cannot-be-negative ()
+  (should-error (slices "123" -1)))
+
+
+(ert-deftest empty-series-is-invalid ()
+  (should-error (slices "" 1)))
+
+
+(provide 'series-test)
+;;; series-test.el ends here

exercises/practice/series/series.el

@@ -0,0 +1,14 @@
+;;; series.el --- Series (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(defun slices (series slice-length)
+  (error "Delete this S-Expression and write your own implementation"))
+
+
+(provide 'series)
+;;; series.el ends here
+