Add spiral-matrix exercise

config.json

@@ -731,6 +731,14 @@
         "prerequisites": [],
         "difficulty": 5
       },
+      {
+        "slug": "spiral-matrix",
+        "name": "Spiral Matrix",
+        "uuid": "4ce2b869-140a-4d5d-90dd-6fc717ef7696",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "word-count",
         "name": "Word Count",

exercises/practice/spiral-matrix/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Instructions
+
+Given the size, return a square matrix of numbers in spiral order.
+
+The matrix should be filled with natural numbers, starting from 1 in the top-left corner, increasing in an inward, clockwise spiral order, like these examples:
+
+## Examples
+
+### Spiral matrix of size 3
+
+```text
+1 2 3
+8 9 4
+7 6 5
+```
+
+### Spiral matrix of size 4
+
+```text
+ 1  2  3 4
+12 13 14 5
+11 16 15 6
+10  9  8 7
+```

exercises/practice/spiral-matrix/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "spiral-matrix.el"
+    ],
+    "test": [
+      "spiral-matrix-test.el"
+    ],
+    "example": [
+      ".meta/example.el"
+    ]
+  },
+  "blurb": "Given the size, return a square matrix of numbers in spiral order.",
+  "source": "Reddit r/dailyprogrammer challenge #320 [Easy] Spiral Ascension.",
+  "source_url": "https://web.archive.org/web/20230607064729/https://old.reddit.com/r/dailyprogrammer/comments/6i60lr/20170619_challenge_320_easy_spiral_ascension/"
+}

exercises/practice/spiral-matrix/.meta/example.el

@@ -0,0 +1,41 @@
+;;; spiral-matrix.el --- Spiral Matrix (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'cl-lib)
+
+(defun spiral-matrix (size)
+  (let* ((result (make-vector size nil))
+         (value 1)
+         (row 0)
+         (column 0)
+         (side (1- size)))
+    (cl-loop for r below size
+      do (aset result r (make-vector size (* size size))))
+    (while (>= side 1)
+      (cl-loop repeat side
+        do (aset (aref result row) column value)
+        do (setq value (1+ value))
+        do (setq column (1+ column)))
+      (cl-loop repeat side
+        do (aset (aref result row) column value)
+        do (setq value (1+ value))
+        do (setq row (1+ row)))
+      (cl-loop repeat side
+        do (aset (aref result row) column value)
+        do (setq value (1+ value))
+        do (setq column (1- column)))
+      (cl-loop repeat side
+        do (aset (aref result row) column value)
+        do (setq value (1+ value))
+        do (setq row (1- row)))
+      (setq row (1+ row))
+      (setq column (1+ column))
+      (setq side (- side 2)))
+    result))
+
+(provide 'spiral-matrix)
+;;; spiral-matrix.el ends here
+

exercises/practice/spiral-matrix/.meta/tests.toml

@@ -0,0 +1,28 @@
+# 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.
+
+[8f584201-b446-4bc9-b132-811c8edd9040]
+description = "empty spiral"
+
+[e40ae5f3-e2c9-4639-8116-8a119d632ab2]
+description = "trivial spiral"
+
+[cf05e42d-eb78-4098-a36e-cdaf0991bc48]
+description = "spiral of size 2"
+
+[1c475667-c896-4c23-82e2-e033929de939]
+description = "spiral of size 3"
+
+[05ccbc48-d891-44f5-9137-f4ce462a759d]
+description = "spiral of size 4"
+
+[f4d2165b-1738-4e0c-bed0-c459045ae50d]
+description = "spiral of size 5"

exercises/practice/spiral-matrix/spiral-matrix-test.el

@@ -0,0 +1,47 @@
+;;; spiral-matrix-test.el --- Tests for Spiral Matrix (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(load-file "spiral-matrix.el")
+(declare-function spiral-matrix "spiral-matrix.el" (size))
+
+
+(ert-deftest empty-spiral ()
+  (should (equal [] (spiral-matrix 0))))
+
+
+(ert-deftest trivial-spiral ()
+  (should (equal [[1]] (spiral-matrix 1))))
+
+
+(ert-deftest spiral-of-size-2 ()
+  (should (equal [[1 2]
+                  [4 3]] (spiral-matrix 2))))
+
+
+(ert-deftest spiral-of-size-3 ()
+  (should (equal [[1 2 3]
+                  [8 9 4]
+                  [7 6 5]] (spiral-matrix 3))))
+
+
+(ert-deftest spiral-of-size-4 ()
+  (should (equal [[1 2 3 4]
+                  [12 13 14 5]
+                  [11 16 15 6]
+                  [10 9 8 7]] (spiral-matrix 4))))
+
+
+(ert-deftest spiral-of-size-5 ()
+  (should (equal [[1 2 3 4 5]
+                  [16 17 18 19 6]
+                  [15 24 25 20 7]
+                  [14 23 22 21 8]
+                  [13 12 11 10 9]] (spiral-matrix 5))))
+
+
+(provide 'spiral-matrix-test)
+;;; spiral-matrix-test.el ends here

exercises/practice/spiral-matrix/spiral-matrix.el

@@ -0,0 +1,14 @@
+;;; spiral-matrix.el --- Spiral Matrix (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(defun spiral-matrix (size)
+  (error "Delete this S-Expression and write your own implementation"))
+
+
+(provide 'spiral-matrix)
+;;; spiral-matrix.el ends here
+