Add rectangles exercise

config.json

@@ -982,6 +982,14 @@
           "control_flow_loops"
         ]
       },
+      {
+        "slug": "rectangles",
+        "name": "Rectangles",
+        "uuid": "61fdcaf4-c2f6-4d13-a5ed-743997d567a6",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 7
+      },
       {
         "slug": "bank-account",
         "name": "Bank Account",

exercises/practice/rectangles/.docs/instructions.md

@@ -0,0 +1,63 @@
+# Instructions
+
+Count the rectangles in an ASCII diagram like the one below.
+
+```text
+   +--+
+  ++  |
++-++--+
+|  |  |
++--+--+
+```
+
+The above diagram contains these 6 rectangles:
+
+```text
+
+
++-----+
+|     |
++-----+
+```
+
+```text
+   +--+
+   |  |
+   |  |
+   |  |
+   +--+
+```
+
+```text
+   +--+
+   |  |
+   +--+
+
+
+```
+
+```text
+
+
+   +--+
+   |  |
+   +--+
+```
+
+```text
+
+
++--+
+|  |
++--+
+```
+
+```text
+
+  ++
+  ++
+
+
+```
+
+You may assume that the input is always a proper rectangle (i.e. the length of every line equals the length of the first line).

exercises/practice/rectangles/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "rectangles.el"
+    ],
+    "test": [
+      "rectangles-test.el"
+    ],
+    "example": [
+      ".meta/example.el"
+    ]
+  },
+  "blurb": "Count the rectangles in an ASCII diagram."
+}

exercises/practice/rectangles/.meta/example.el

@@ -0,0 +1,36 @@
+;;; rectangles.el --- Rectangles (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'cl-lib)
+
+(defun bottom (row left right)
+  (cl-loop for col from left to right
+           always (memq (aref row col) '(?+ ?-))))
+
+(defun sides (rows left right)
+  (cl-loop for rows on rows
+           for row = (car rows)
+           while (and (memq (aref row left) '(?+ ?|))
+                      (memq (aref row right) '(?+ ?|)))
+           when (and (= ?+ (aref row left))
+                     (= ?+ (aref row right)))
+           count (bottom row left right)))
+
+(defun top (first rest)
+  (cl-loop for right from 1 below (length first)
+           when (= ?+ (aref first right))
+           sum (cl-loop for left from (1- right) downto 0
+                        while (memq (aref first left) '(?+ ?-))
+                        when (= ?+ (aref first left))
+                        sum (sides rest left right))))
+
+(defun rectangles (strings)
+  (cl-loop for strings on strings
+           sum (top (car strings) (cdr strings))))
+
+
+(provide 'rectangles)
+;;; rectangles.el ends here

exercises/practice/rectangles/.meta/tests.toml

@@ -0,0 +1,52 @@
+# 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.
+
+[485b7bab-4150-40aa-a8db-73013427d08c]
+description = "no rows"
+
+[076929ed-27e8-45dc-b14b-08279944dc49]
+description = "no columns"
+
+[0a8abbd1-a0a4-4180-aa4e-65c1b1a073fa]
+description = "no rectangles"
+
+[a4ba42e9-4e7f-4973-b7c7-4ce0760ac6cd]
+description = "one rectangle"
+
+[ced06550-83da-4d23-98b7-d24152e0db93]
+description = "two rectangles without shared parts"
+
+[5942d69a-a07c-41c8-8b93-2d13877c706a]
+description = "five rectangles with shared parts"
+
+[82d70be4-ab37-4bf2-a433-e33778d3bbf1]
+description = "rectangle of height 1 is counted"
+
+[57f1bc0e-2782-401e-ab12-7c01d8bfc2e0]
+description = "rectangle of width 1 is counted"
+
+[ef0bb65c-bd80-4561-9535-efc4067054f9]
+description = "1x1 square is counted"
+
+[e1e1d444-e926-4d30-9bf3-7d8ec9a9e330]
+description = "only complete rectangles are counted"
+
+[ca021a84-1281-4a56-9b9b-af14113933a4]
+description = "rectangles can be of different sizes"
+
+[51f689a7-ef3f-41ae-aa2f-5ea09ad897ff]
+description = "corner is required for a rectangle to be complete"
+
+[d78fe379-8c1b-4d3c-bdf7-29bfb6f6dc66]
+description = "large input with many rectangles"
+
+[6ef24e0f-d191-46da-b929-4faca24b4cd2]
+description = "rectangles must have four sides"

exercises/practice/rectangles/rectangles-test.el

@@ -0,0 +1,147 @@
+;;; rectangles-test.el --- Tests for Rectangles (exercism)  -*- lexical-binding: t; -*-
+
+;;; Commentary:
+
+;;; Code:
+
+
+(load-file "rectangles.el")
+(declare-function rectangles "rectangles.el" (strings))
+
+
+(ert-deftest no-rows ()
+  (should (= 0
+             (rectangles '()))))
+
+
+(ert-deftest no-columns ()
+  (should (= 0
+             (rectangles '("")))))
+
+
+(ert-deftest no-rectangles ()
+  (should (= 0
+             (rectangles '(" ")))))
+
+
+(ert-deftest one-rectangle ()
+  (should (= 1
+             (rectangles '("+-+"
+                           "| |"
+                           "+-+")))))
+
+
+(ert-deftest two-rectangles-without-shared-parts ()
+  (should (= 2
+             (rectangles '("  +-+"
+                           "  | |"
+                           "+-+-+"
+                           "| |  "
+                           "+-+  ")))))
+
+
+(ert-deftest five-rectangles-with-shared-parts ()
+  (should (= 5
+             (rectangles '("  +-+"
+                           "  | |"
+                           "+-+-+"
+                           "| | |"
+                           "+-+-+")))))
+
+
+(ert-deftest rectangle-of-height-1-is-counted ()
+  (should (= 1
+             (rectangles '("+--+"
+                           "+--+")))))
+
+
+(ert-deftest rectangle-of-width-1-is-counted ()
+  (should (= 1
+             (rectangles '("++"
+                           "||"
+                           "++")))))
+
+
+(ert-deftest 1x1-square-is-counted ()
+  (should (= 1
+             (rectangles '("++"
+                           "++")))))
+
+
+(ert-deftest only-complete-rectangles-are-counted ()
+  (should (= 1
+             (rectangles '("  +-+"
+                           "    |"
+                           "+-+-+"
+                           "| | -"
+                           "+-+-+")))))
+
+
+(ert-deftest rectangles-can-be-of-different-sizes ()
+  (should (= 3
+             (rectangles '("+------+----+"
+                           "|      |    |"
+                           "+---+--+    |"
+                           "|   |       |"
+                           "+---+-------+")))))
+
+
+(ert-deftest corner-is-required-for-a-rectangle-to-be-complete ()
+  (should (= 2
+             (rectangles '("+------+----+"
+                           "|      |    |"
+                           "+------+    |"
+                           "|   |       |"
+                           "+---+-------+")))))
+
+
+(ert-deftest large-input-with-many-rectangles ()
+  (should (= 60
+             (rectangles '("+---+--+----+"
+                           "|   +--+----+"
+                           "+---+--+    |"
+                           "|   +--+----+"
+                           "+---+--+--+-+"
+                           "+---+--+--+-+"
+                           "+------+  | |"
+                           "          +-+")))))
+
+
+(ert-deftest rectangles-must-have-four-sides ()
+  (should (= 5
+             (rectangles '("+-+ +-+"
+                           "| | | |"
+                           "+-+-+-+"
+                           "  | |  "
+                           "+-+-+-+"
+                           "| | | |"
+                           "+-+ +-+")))))
+
+
+(ert-deftest very-large-input ()
+  (should (= 2063
+             (rectangles '("      +-----+--------+    +-----+ "
+                           "++---++-----+--------+---++-----++"
+                           "||+--++-----+-+-++   |   ||     ||"
+                           "|||  ||     +-+-++-+ |   ||     ||"
+                           "|||  ||     | | || | |   ||     ||"
+                           "||| +++-----+-+-++-+-+---++-+   ||"
+                           "||| |||     | | || | |+--++-+-+ ||"
+                           "||| +++---+-+-+-++-+-++--++-+ | ||"
+                           "||| |||+--+-+-+-+| | |+--++---+ ||"
+                           "||| ||||  | | | || | |+-+||     ||"
+                           "||+-++++--+-+++-++-+-++-+++---++||"
+                           "||  |+++--+-+++-+--+-+| |||   ||||"
+                           "+++-+++++---++--+-++-++-+++---+|||"
+                           " |+-+++++---++--+ || || |||   ||||"
+                           " |  +++++---++--+-++-++-++++  ||||"
+                           " |   ||||   |+----++-++-++++--+++|"
+                           " |   |+++---+|    || || ||    || |"
+                           "+++  |||+---++----+| || ||    || |"
+                           "|||  +++----++----++-++-++----++-+"
+                           "+++---++----++-----+-++-++----++  "
+                           "                      +-+         ")))))
+
+
+(provide 'rectangles-test)
+;;; rectangles-test.el ends here

exercises/practice/rectangles/rectangles.el

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