feat: add crypto square exercise (#60)

config.json

@@ -349,6 +349,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 3
+      },
+      {
+        "slug": "crypto-square",
+        "name": "Crypto Square",
+        "uuid": "f5f0f47a-f777-499e-a1fd-61bbff94cceb",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
       }
     ]
   },

exercises/practice/crypto-square/.docs/instructions.md

@@ -0,0 +1,71 @@
+# Instructions
+
+Implement the classic method for composing secret messages called a square code.
+
+Given an English text, output the encoded version of that text.
+
+First, the input is normalized: the spaces and punctuation are removed from the English text and the message is down-cased.
+
+Then, the normalized characters are broken into rows.
+These rows can be regarded as forming a rectangle when printed with intervening newlines.
+
+For example, the sentence
+
+```text
+"If man was meant to stay on the ground, god would have given us roots."
+```
+
+is normalized to:
+
+```text
+"ifmanwasmeanttostayonthegroundgodwouldhavegivenusroots"
+```
+
+The plaintext should be organized into a rectangle as square as possible.
+The size of the rectangle should be decided by the length of the message.
+
+If `c` is the number of columns and `r` is the number of rows, then for the rectangle `r` x `c` find the smallest possible integer `c` such that:
+
+- `r * c >= length of message`,
+- and `c >= r`,
+- and `c - r <= 1`.
+
+Our normalized text is 54 characters long, dictating a rectangle with `c = 8` and `r = 7`:
+
+```text
+"ifmanwas"
+"meanttos"
+"tayonthe"
+"groundgo"
+"dwouldha"
+"vegivenu"
+"sroots  "
+```
+
+The coded message is obtained by reading down the columns going left to right.
+
+The message above is coded as:
+
+```text
+"imtgdvsfearwermayoogoanouuiontnnlvtwttddesaohghnsseoau"
+```
+
+Output the encoded text in chunks that fill perfect rectangles `(r X c)`, with `c` chunks of `r` length, separated by spaces.
+For phrases that are `n` characters short of the perfect rectangle, pad each of the last `n` chunks with a single trailing space.
+
+```text
+"imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau "
+```
+
+Notice that were we to stack these, we could visually decode the ciphertext back in to the original message:
+
+```text
+"imtgdvs"
+"fearwer"
+"mayoogo"
+"anouuio"
+"ntnnlvt"
+"wttddes"
+"aohghn "
+"sseoau "
+```

exercises/practice/crypto-square/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glaxxie"
+  ],
+  "files": {
+    "solution": [
+      "crypto-square.ua"
+    ],
+    "test": [
+      "tests.ua"
+    ],
+    "example": [
+      ".meta/example.ua"
+    ]
+  },
+  "blurb": "Implement the classic method for composing secret messages called a square code.",
+  "source": "J Dalbey's Programming Practice problems",
+  "source_url": "https://users.csc.calpoly.edu/~jdalbey/103/Projects/ProgrammingPractice.html"
+}

exercises/practice/crypto-square/.meta/example.ua

@@ -0,0 +1,8 @@
+# Implement the classic method for composing secret messages called a square code
+
+CleanStr     ← |1 ⊢⍉regex "\\w" ¯⌵
+EmptyStr     ← |0 [0 0]
+NoneEmptyStr ← |1 [⌈÷:⟜(.⌈√)⧻]
+GetRowNCol   ← |1 ⨬(NoneEmptyStr|EmptyStr) ⊸(=0 ⧻)
+# Ciphertext ? Plaintext
+Ciphertext   ← |1 /$"_ _" ≡(/$"__") ⍉↯⊙(⬚" "↙) ⟜/× GetRowNCol .CleanStr

exercises/practice/crypto-square/.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.
+
+[407c3837-9aa7-4111-ab63-ec54b58e8e9f]
+description = "empty plaintext results in an empty ciphertext"
+
+[aad04a25-b8bb-4304-888b-581bea8e0040]
+description = "normalization results in empty plaintext"
+
+[64131d65-6fd9-4f58-bdd8-4a2370fb481d]
+description = "Lowercase"
+
+[63a4b0ed-1e3c-41ea-a999-f6f26ba447d6]
+description = "Remove spaces"
+
+[1b5348a1-7893-44c1-8197-42d48d18756c]
+description = "Remove punctuation"
+
+[8574a1d3-4a08-4cec-a7c7-de93a164f41a]
+description = "9 character plaintext results in 3 chunks of 3 characters"
+
+[a65d3fa1-9e09-43f9-bcec-7a672aec3eae]
+description = "8 character plaintext results in 3 chunks, the last one with a trailing space"
+
+[fbcb0c6d-4c39-4a31-83f6-c473baa6af80]
+description = "54 character plaintext results in 7 chunks, the last two with trailing spaces"

exercises/practice/crypto-square/crypto-square.ua

@@ -0,0 +1,3 @@
+# Implement the classic method for composing secret messages called a square code
+# Ciphertext ? Plaintext
+Ciphertext  ← |1 ⊙(⍤ "Please implement Ciphertext" 0)

exercises/practice/crypto-square/tests.ua

@@ -0,0 +1,25 @@
+~ "crypto-square.ua" ~ Ciphertext
+
+# empty plaintext results in an empty ciphertext
+⍤⤙≍ "" Ciphertext ""
+
+# normalization results in empty plaintext
+⍤⤙≍ "" Ciphertext "... --- ..."
+
+# Lowercase
+⍤⤙≍ "a" Ciphertext "A"
+
+# Remove spaces
+⍤⤙≍ "b" Ciphertext "  b "
+
+# Remove punctuation
+⍤⤙≍ "1" Ciphertext "@1,%!"
+
+# 9 character plaintext results in 3 chunks of 3 characters
+⍤⤙≍ "tsf hiu isn" Ciphertext "This is fun!"
+
+# 8 character plaintext results in 3 chunks, the last one with a trailing space
+⍤⤙≍ "clu hlt io " Ciphertext "Chill out."
+
+# 54 character plaintext results in 7 chunks, the last two with trailing spaces
+⍤⤙≍ "imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau " Ciphertext "If man was meant to stay on the ground, god would have given us roots."