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Add Roman Numerals exercise (#77)
* Add Roman Numerals exercise * Add instructions.append.md
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‎config.json

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"prerequisites": [],
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"difficulty": 8
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},
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{
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"slug": "roman-numerals",
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"name": "Roman Numerals",
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"uuid": "f109325a-2bbb-46d7-a7ed-fe8484509985",
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"practices": [],
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"prerequisites": [],
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"difficulty": 8
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},
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{
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"slug": "etl",
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"name": "ETL",

‎exercises/practice/roman-numerals/.docs/instructions.append.md

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# SQLite specific instructions
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This exercise requires you set the `result` column of the `roman-numerals` table to the correct value based on the number found in the `number` column.
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## Table Schema
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```sql
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CREATE TABLE "roman-numerals" ("number" INT, "result" TEXT);
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```

‎exercises/practice/roman-numerals/.docs/instructions.md

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# Introduction
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Your task is to convert a number from Arabic numerals to Roman numerals.
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For this exercise, we are only concerned about traditional Roman numerals, in which the largest number is MMMCMXCIX (or 3,999).
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~~~~exercism/note
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There are lots of different ways to convert between Arabic and Roman numerals.
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We recommend taking a naive approach first to familiarise yourself with the concept of Roman numerals and then search for more efficient methods.
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Make sure to check out our Deep Dive video at the end to explore the different approaches you can take!
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~~~~

‎exercises/practice/roman-numerals/.docs/introduction.md

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# Description
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Today, most people in the world use Arabic numerals (0–9).
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But if you travelled back two thousand years, you'd find that most Europeans were using Roman numerals instead.
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To write a Roman numeral we use the following Latin letters, each of which has a value:
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| M | D | C | L | X | V | I |
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| ---- | --- | --- | --- | --- | --- | --- |
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| 1000 | 500 | 100 | 50 | 10 | 5 | 1 |
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A Roman numeral is a sequence of these letters, and its value is the sum of the letters' values.
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For example, `XVIII` has the value 18 (`10 + 5 + 1 + 1 + 1 = 18`).
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There's one rule that makes things trickier though, and that's that **the same letter cannot be used more than three times in succession**.
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That means that we can't express numbers such as 4 with the seemingly natural `IIII`.
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Instead, for those numbers, we use a subtraction method between two letters.
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So we think of `4` not as `1 + 1 + 1 + 1` but instead as `5 - 1`.
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And slightly confusingly to our modern thinking, we write the smaller number first.
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This applies only in the following cases: 4 (`IV`), 9 (`IX`), 40 (`XL`), 90 (`XC`), 400 (`CD`) and 900 (`CM`).
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Order matters in Roman numerals!
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Letters (and the special compounds above) must be ordered by decreasing value from left to right.
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Here are some examples:
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```text
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105 => CV
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---- => --
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100 => C
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+ 5 => V
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```
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```text
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106 => CVI
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---- => --
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100 => C
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+ 5 => V
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+ 1 => I
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```
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```text
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104 => CIV
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---- => ---
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100 => C
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+ 4 => IV
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```
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And a final more complex example:
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```text
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1996 => MCMXCVI
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----- => -------
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1000 => M
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+ 900 => CM
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+ 90 => XC
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+ 5 => V
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+ 1 => I
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```

‎exercises/practice/roman-numerals/.meta/config.json

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{
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"authors": [
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"Steffan153"
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],
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"files": {
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"solution": [
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"roman-numerals.sql"
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],
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"test": [
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"roman-numerals_test.sql"
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],
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"example": [
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".meta/example.sql"
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],
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"editor": [
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"data.csv"
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]
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},
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"blurb": "Convert modern Arabic numbers into Roman numerals.",
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"source": "The Roman Numeral Kata",
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"source_url": "https://codingdojo.org/kata/RomanNumerals/"
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}

‎exercises/practice/roman-numerals/.meta/example.sql

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ALTER TABLE "roman-numerals"
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ADD temp_num TEXT DEFAULT '';
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PRAGMA recursive_triggers = ON;
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CREATE TRIGGER IF NOT EXISTS update_roman_numerals
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AFTER UPDATE
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ON "roman-numerals"
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WHEN LENGTH(NEW.temp_num) > 0
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BEGIN
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UPDATE "roman-numerals"
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SET result =
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-- we encode the roman numerals in base 10
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-- to add a digit, we translate IVXLC => XLCDM (multiply by ten)
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-- and then add the digit at the end
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REPLACE(REPLACE(REPLACE(REPLACE(REPLACE(result, 'C', 'M'), 'L', 'D'), 'X', 'C'), 'V', 'L'), 'I', 'X') ||
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CASE SUBSTR(temp_num, 1, 1)
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WHEN '0' THEN ''
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WHEN '1' THEN 'I'
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WHEN '2' THEN 'II'
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WHEN '3' THEN 'III'
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WHEN '4' THEN 'IV'
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WHEN '5' THEN 'V'
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WHEN '6' THEN 'VI'
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WHEN '7' THEN 'VII'
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WHEN '8' THEN 'VIII'
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WHEN '9' THEN 'IX'
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END,
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temp_num = SUBSTR(temp_num, 2)
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WHERE temp_num = NEW.temp_num;
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END;
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UPDATE "roman-numerals"
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SET temp_num = number || '';

‎exercises/practice/roman-numerals/.meta/tests.toml

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# This is an auto-generated file.
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#
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# Regenerating this file via `configlet sync` will:
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# - Recreate every `description` key/value pair
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# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
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# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
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# - Preserve any other key/value pair
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#
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# As user-added comments (using the # character) will be removed when this file
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# is regenerated, comments can be added via a `comment` key.
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[19828a3a-fbf7-4661-8ddd-cbaeee0e2178]
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description = "1 is I"
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[f088f064-2d35-4476-9a41-f576da3f7b03]
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description = "2 is II"
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[b374a79c-3bea-43e6-8db8-1286f79c7106]
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description = "3 is III"
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[05a0a1d4-a140-4db1-82e8-fcc21fdb49bb]
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description = "4 is IV"
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[57c0f9ad-5024-46ab-975d-de18c430b290]
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description = "5 is V"
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[20a2b47f-e57f-4797-a541-0b3825d7f249]
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description = "6 is VI"
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[ff3fb08c-4917-4aab-9f4e-d663491d083d]
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description = "9 is IX"
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[6d1d82d5-bf3e-48af-9139-87d7165ed509]
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description = "16 is XVI"
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[2bda64ca-7d28-4c56-b08d-16ce65716cf6]
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description = "27 is XXVII"
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[a1f812ef-84da-4e02-b4f0-89c907d0962c]
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description = "48 is XLVIII"
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[607ead62-23d6-4c11-a396-ef821e2e5f75]
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description = "49 is XLIX"
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[d5b283d4-455d-4e68-aacf-add6c4b51915]
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description = "59 is LIX"
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[4465ffd5-34dc-44f3-ada5-56f5007b6dad]
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description = "66 is LXVI"
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[46b46e5b-24da-4180-bfe2-2ef30b39d0d0]
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description = "93 is XCIII"
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[30494be1-9afb-4f84-9d71-db9df18b55e3]
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description = "141 is CXLI"
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[267f0207-3c55-459a-b81d-67cec7a46ed9]
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description = "163 is CLXIII"
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[902ad132-0b4d-40e3-8597-ba5ed611dd8d]
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description = "166 is CLXVI"
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[cdb06885-4485-4d71-8bfb-c9d0f496b404]
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description = "402 is CDII"
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[6b71841d-13b2-46b4-ba97-dec28133ea80]
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description = "575 is DLXXV"
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[dacb84b9-ea1c-4a61-acbb-ce6b36674906]
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description = "666 is DCLXVI"
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[432de891-7fd6-4748-a7f6-156082eeca2f]
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description = "911 is CMXI"
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[e6de6d24-f668-41c0-88d7-889c0254d173]
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description = "1024 is MXXIV"
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[efbe1d6a-9f98-4eb5-82bc-72753e3ac328]
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description = "1666 is MDCLXVI"
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[bb550038-d4eb-4be2-a9ce-f21961ac3bc6]
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description = "3000 is MMM"
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[3bc4b41c-c2e6-49d9-9142-420691504336]
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description = "3001 is MMMI"
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[2f89cad7-73f6-4d1b-857b-0ef531f68b7e]
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description = "3888 is MMMDCCCLXXXVIII"
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[4e18e96b-5fbb-43df-a91b-9cb511fe0856]
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description = "3999 is MMMCMXCIX"

‎exercises/practice/roman-numerals/create_fixture.sql

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DROP TABLE IF EXISTS "roman-numerals";
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CREATE TABLE "roman-numerals" (
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"number" INT,
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"result" TEXT
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);
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.mode csv
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.import ./data.csv roman-numerals

‎exercises/practice/roman-numerals/data.csv

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1,""
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2,""
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3,""
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4,""
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5,""
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6,""
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9,""
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16,""
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27,""
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48,""
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49,""
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59,""
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66,""
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93,""
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141,""
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163,""
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166,""
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402,""
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575,""
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666,""
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911,""
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1024,""
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1666,""
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3000,""
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3001,""
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3888,""
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3999,""

‎exercises/practice/roman-numerals/roman-numerals.sql

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-- Schema: CREATE TABLE "roman-numerals" ("number" INT, "result" TEXT);
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-- Task: update the roman-numerals table and set the result based on the number.

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