Add practice exercise: crypto-square

config.json

@@ -346,6 +346,14 @@
         "prerequisites": [],
         "difficulty": 8
       },
+      {
+        "slug": "crypto-square",
+        "name": "Crypto Square",
+        "uuid": "9fc46c57-3011-4dff-b4af-9259aeb2e170",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 8
+      },
       {
         "slug": "diamond",
         "name": "Diamond",

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": [
+    "jimmytty"
+  ],
+  "files": {
+    "solution": [
+      "crypto-square.sql"
+    ],
+    "test": [
+      "crypto-square_test.sql"
+    ],
+    "example": [
+      ".meta/example.sql"
+    ]
+  },
+  "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.sql

@@ -0,0 +1,106 @@
+DROP TABLE IF EXISTS tmp;
+CREATE TEMPORARY TABLE tmp (
+  plaintext  TEXT PRIMARY KEY,
+  normalized TEXT
+);
+INSERT INTO tmp
+SELECT plaintext, COALESCE(
+       (WITH RECURSIVE rcte (string, chr) AS (
+         VALUES (LOWER(plaintext), NULL)
+         UNION ALL
+         SELECT SUBSTR(string, 2),
+                IIF(GLOB('[^0-9a-z]', SUBSTR(string, 1, 1)),
+                    NULL,
+                    SUBSTR(string, 1, 1))
+           FROM rcte
+          WHERE string <> ''
+       )
+       SELECT GROUP_CONCAT(chr, '')
+         FROM rcte
+        WHERE chr NOTNULL
+       ), '')
+  FROM "crypto-square"
+;
+
+ALTER TABLE tmp ADD COLUMN cols INTEGER;
+UPDATE tmp SET cols = ROUND(CEIL(sqrt(LENGTH(normalized))));
+
+ALTER TABLE tmp ADD COLUMN square TEXT;
+WITH to_square (plaintext, string) AS (
+  SELECT plaintext,
+         (WITH RECURSIVE rcte (string, chr) AS (
+           VALUES (tmp.normalized, NULL)
+           UNION ALL
+           SELECT SUBSTR(string, 2), SUBSTR(string, 1, 1)
+             FROM rcte
+            WHERE string <> ''
+         )
+         SELECT GROUP_CONCAT(chunk, CHAR(10))
+           FROM (
+             SELECT PRINTF('%-*s', tmp.cols, GROUP_CONCAT(chr, '')) chunk
+               FROM (
+                 SELECT (ROW_NUMBER() OVER () - 1) / tmp.cols AS gid, chr
+                   FROM rcte
+                  WHERE chr NOTNULL
+               )
+              GROUP BY gid
+           )
+         )
+    FROM tmp
+)
+UPDATE tmp
+   SET square = string
+  FROM to_square
+  WHERE tmp.plaintext = to_square.plaintext
+;
+
+ALTER TABLE tmp ADD COLUMN matrix TEXT;
+WITH to_matrix (plaintext, matrix) AS (
+  SELECT plaintext,
+         (WITH RECURSIVE split_lines (text, array) AS (
+           VALUES (tmp.square || CHAR(10), NULL)
+           UNION ALL
+           SELECT
+           SUBSTR(text, INSTR(text, CHAR(10))+1),
+           (WITH RECURSIVE split_chars (string, chr) AS (
+             VALUES (PRINTF('%-*s',
+                            tmp.cols,
+                            SUBSTR(text, 1, INSTR(text, CHAR(10)) - 1)),
+                            NULL)
+                            UNION ALL
+                            SELECT SUBSTR(string, 2), SUBSTR(string, 1, 1)
+                            FROM split_chars
+                            WHERE string <> ''
+           ) SELECT JSON_GROUP_ARRAY(chr) FROM split_chars WHERE chr NOTNULL)
+             FROM split_lines
+            WHERE text <> ''
+         )
+         SELECT JSON_GROUP_ARRAY(JSON(array))
+           FROM split_lines
+          WHERE array NOTNULL
+         )
+    FROM tmp
+)
+UPDATE tmp
+   SET matrix = to_matrix.matrix
+  FROM to_matrix
+ WHERE tmp.plaintext = to_matrix.plaintext
+;
+
+WITH to_encode (plaintext, encoded) AS (
+SELECT plaintext, COALESCE(
+       (SELECT GROUP_CONCAT(line, ' ')
+          FROM (
+            SELECT GROUP_CONCAT(j.value, '') line
+              FROM JSON_TREE(tmp.matrix) j
+             WHERE j.type <> 'array'
+             GROUP BY SUBSTR(j.fullkey, INSTR(j.fullkey, ']['))
+          )
+       ), '')
+  FROM tmp
+)
+UPDATE "crypto-square" AS cs
+    SET result = encoded
+    FROM to_encode AS te
+    WHERE cs.plaintext = te.plaintext
+;

exercises/practice/crypto-square/.meta/tests.toml

@@ -0,0 +1,39 @@
+# 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"
+include = false
+
+[33fd914e-fa44-445b-8f38-ff8fbc9fe6e6]
+description = "54 character plaintext results in 8 chunks, the last two with trailing spaces"
+reimplements = "fbcb0c6d-4c39-4a31-83f6-c473baa6af80"

exercises/practice/crypto-square/create_fixture.sql

@@ -0,0 +1,10 @@
+DROP TABLE IF EXISTS "crypto-square";
+CREATE TABLE "crypto-square" (
+  plaintext TEXT NOT NULL,
+  result    TEXT
+);
+
+.mode csv
+.import ./data.csv "crypto-square"
+
+UPDATE "crypto-square" SET result = NULL;

exercises/practice/crypto-square/create_test_table.sql

@@ -0,0 +1,27 @@
+DROP TABLE IF EXISTS tests;
+CREATE TABLE IF NOT EXISTS tests (
+  -- uuid and description are taken from the test.toml file
+  uuid TEXT PRIMARY KEY,
+  description TEXT NOT NULL,
+  -- The following section is needed by the online test-runner
+  status TEXT DEFAULT 'fail',
+  message TEXT,
+  output TEXT,
+  test_code TEXT,
+  task_id INTEGER DEFAULT NULL,
+  -- Here are columns for the actual tests
+  plaintext TEXT NOT NULL,
+  expected TEXT NOT NULL
+);
+
+
+INSERT INTO tests (uuid, description, plaintext, expected)
+VALUES
+('407c3837-9aa7-4111-ab63-ec54b58e8e9f', 'empty plaintext results in an empty ciphertext', '', ''),
+('aad04a25-b8bb-4304-888b-581bea8e0040', 'normalization results in empty plaintext', '... --- ...', ''),
+('64131d65-6fd9-4f58-bdd8-4a2370fb481d', 'Lowercase', 'A', 'a'),
+('63a4b0ed-1e3c-41ea-a999-f6f26ba447d6', 'Remove spaces', '  b ', 'b'),
+('1b5348a1-7893-44c1-8197-42d48d18756c', 'Remove punctuation', '@1,%!', '1'),
+('8574a1d3-4a08-4cec-a7c7-de93a164f41a', '9 character plaintext results in 3 chunks of 3 characters', 'This is fun!', 'tsf hiu isn'),
+('a65d3fa1-9e09-43f9-bcec-7a672aec3eae', '8 character plaintext results in 3 chunks, the last one with a trailing space', 'Chill out.', 'clu hlt io '),
+('33fd914e-fa44-445b-8f38-ff8fbc9fe6e6', '54 character plaintext results in 8 chunks, the last two with trailing spaces', 'If man was meant to stay on the ground, god would have given us roots.', 'imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau ');

exercises/practice/crypto-square/crypto-square.sql

@@ -0,0 +1,7 @@
+-- Schema:
+-- CREATE TABLE "crypto-square" (
+--   plaintext TEXT NOT NULL,
+--   result    TEXT
+-- );
+--
+-- Task: update the crypto-square table and set the result column based on the plaintext.

exercises/practice/crypto-square/crypto-square_test.sql

@@ -0,0 +1,40 @@
+-- Create database:
+.read ./create_fixture.sql
+
+-- Read user student solution and save any output as markdown in user_output.md:
+.mode markdown
+.output user_output.md
+.read ./crypto-square.sql
+.output
+
+-- Create a clean testing environment:
+.read ./create_test_table.sql
+
+-- Comparison of user input and the tests updates the status for each test:
+UPDATE tests
+   SET status = 'pass'
+  FROM (SELECT plaintext, result FROM "crypto-square") AS actual
+ WHERE (actual.plaintext, actual.result) = (tests.plaintext, tests.expected);
+
+-- Update message for failed tests to give helpful information:
+UPDATE tests
+   SET message = (
+         'Result for "'
+         || tests.plaintext
+         || '"' || ' is <'
+         || COALESCE(actual.result, 'NULL')
+         || '> but should be <'
+         || tests.expected
+         || '>'
+      )
+  FROM (SELECT plaintext, result FROM "crypto-square") AS actual
+ WHERE actual.plaintext = tests.plaintext AND tests.status = 'fail';
+
+-- Save results to ./output.json (needed by the online test-runner)
+.mode json
+.once './output.json'
+SELECT description, status, message, output, test_code, task_id FROM tests;
+
+-- Display test results in readable form for the student:
+.mode table
+SELECT description, status, message FROM tests;

exercises/practice/crypto-square/data.csv

@@ -0,0 +1,8 @@
+"",
+"... --- ...",
+"A",
+"  b ",
+"@1,%!",
+"This is fun!",
+"Chill out.",
+"If man was meant to stay on the ground, god would have given us roots.",