Add pascals-triangle exercise

config.json

@@ -558,6 +558,17 @@
           "math"
         ]
       },
+      {
+        "slug": "pascals-triangle",
+        "name": "Pascal's Triangle",
+        "uuid": "cc71a6d5-efb2-4054-bf72-102b3e96e0bc",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4,
+        "topics": [
+          "math"
+        ]
+      },
       {
         "slug": "affine-cipher",
         "name": "Affine Cipher",

exercises/practice/pascals-triangle/.docs/instructions.md

@@ -0,0 +1,14 @@
+# Instructions
+
+Compute Pascal's triangle up to a given number of rows.
+
+In Pascal's Triangle each number is computed by adding the numbers to the right and left of the current position in the previous row.
+
+```text
+    1
+   1 1
+  1 2 1
+ 1 3 3 1
+1 4 6 4 1
+# ... etc
+```

exercises/practice/pascals-triangle/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "pascals-triangle.el"
+    ],
+    "test": [
+      "pascals-triangle-test.el"
+    ],
+    "example": [
+      ".meta/example.el"
+    ]
+  },
+  "blurb": "Compute Pascal's triangle up to a given number of rows.",
+  "source": "Pascal's Triangle at Wolfram Math World",
+  "source_url": "https://www.wolframalpha.com/input/?i=Pascal%27s+triangle"
+}

exercises/practice/pascals-triangle/.meta/example.el

@@ -0,0 +1,23 @@
+;;; pascals-triangle.el --- Pascal's Triangle (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'cl-lib)
+
+(defun rows (count)
+  (let ((result (make-vector count nil))
+        (current nil)
+        (previous nil))
+    (cl-loop for r below count
+      do (setq current (make-vector (1+ r) 1))
+      do (cl-loop for c from 1 below r
+           do (aset current c (+ (aref previous (1- c)) (aref previous c))))
+      do (aset result r current)
+      do (setq previous current))
+    result))
+
+(provide 'pascals-triangle)
+;;; pascals-triangle.el ends here
+

exercises/practice/pascals-triangle/.meta/tests.toml

@@ -0,0 +1,34 @@
+# 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.
+
+[9920ce55-9629-46d5-85d6-4201f4a4234d]
+description = "zero rows"
+
+[70d643ce-a46d-4e93-af58-12d88dd01f21]
+description = "single row"
+
+[a6e5a2a2-fc9a-4b47-9f4f-ed9ad9fbe4bd]
+description = "two rows"
+
+[97206a99-79ba-4b04-b1c5-3c0fa1e16925]
+description = "three rows"
+
+[565a0431-c797-417c-a2c8-2935e01ce306]
+description = "four rows"
+
+[06f9ea50-9f51-4eb2-b9a9-c00975686c27]
+description = "five rows"
+
+[c3912965-ddb4-46a9-848e-3363e6b00b13]
+description = "six rows"
+
+[6cb26c66-7b57-4161-962c-81ec8c99f16b]
+description = "ten rows"

exercises/practice/pascals-triangle/pascals-triangle-test.el

@@ -0,0 +1,69 @@
+;;; pascals-triangle-test.el --- Tests for Pascal's Triangle (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(load-file "pascals-triangle.el")
+(declare-function rows "pascals-triangle.el" (count))
+
+
+(ert-deftest zero-rows ()
+  (should (equal [] (rows 0))))
+
+
+(ert-deftest single-row ()
+  (should (equal [[1]] (rows 1))))
+
+
+(ert-deftest two-rows ()
+  (should (equal [[1]
+                  [1 1]] (rows 2))))
+
+
+(ert-deftest three-rows ()
+  (should (equal [[1]
+                  [1 1]
+                  [1 2 1]] (rows 3))))
+
+
+(ert-deftest four-rows ()
+  (should (equal [[1]
+                  [1 1]
+                  [1 2 1]
+                  [1 3 3 1]] (rows 4))))
+
+
+(ert-deftest five-rows ()
+  (should (equal [[1]
+                  [1 1]
+                  [1 2 1]
+                  [1 3 3 1]
+                  [1 4 6 4 1]] (rows 5))))
+
+
+(ert-deftest six-rows ()
+  (should (equal [[1]
+                  [1 1]
+                  [1 2 1]
+                  [1 3 3 1]
+                  [1 4 6 4 1]
+                  [1 5 10 10 5 1]] (rows 6))))
+
+
+(ert-deftest ten-rows ()
+  (should (equal [[1]
+                  [1 1]
+                  [1 2 1]
+                  [1 3 3 1]
+                  [1 4 6 4 1]
+                  [1 5 10 10 5 1]
+                  [1 6 15 20 15 6 1]
+                  [1 7 21 35 35 21 7 1]
+                  [1 8 28 56 70 56 28 8 1]
+                  [1 9 36 84 126 126 84 36 9 1]] (rows 10))))
+
+
+(provide 'pascals-triangle-test)
+;;; pascals-triangle-test.el ends here

exercises/practice/pascals-triangle/pascals-triangle.el

@@ -0,0 +1,14 @@
+;;; pascals-triangle.el --- Pascal's Triangle (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(defun rows (count)
+  (error "Delete this S-Expression and write your own implementation"))
+
+
+(provide 'pascals-triangle)
+;;; pascals-triangle.el ends here
+