feat(2023): add solution for challenge #12

2023/challenge-12/README.md

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+# Challenge #12: Is it a valid copy?
+
+At the North Pole, **they still use paper photocopiers.** The elves use them to copy the letters that children send to Santa so they can send them to all the gift departments.
+
+However, **they are very old and don’t work very well.** Every time they make a copy, the quality of the copy slightly decreases, a phenomenon known as generational loss.
+
+**You need to detect if one letter is a copy of another.** The letters are very long and you can’t read them, but you can compare them with an algorithm.
+
+There’s a big **probability** that a character would degrade in each copy (it doesn't always happen!). And when it does, the rule it follows is:
+
+- **The characters from `A` to `Z` degrade from uppercase to lowercase (`A-Z` ⇒ `a-z`)**
+- **Letters degrade in a series of characters in this order: `a-z` ⇒ `#` ⇒ `+` ⇒ `:` ⇒ `.` ⇒ ` `**
+- **Characters that are not letters (like digits) do not degrade.**
+
+Knowing this and receiving the original letter and the copy, you must determine if the copy is a copy of the original.
+
+```js
+checkIsValidCopy('Santa Claus is coming', 'sa#ta cl#us is comin#') // true
+checkIsValidCopy('Santa Claus is coming', 'p#nt: cla#s #s c+min#') // false (for the initial p)
+checkIsValidCopy('Santa Claus', 's#+:. c:. s') // true
+checkIsValidCopy('Santa Claus', 's#+:.#c:. s') // false (there is a # where it should not be)
+```
+
+To understand how photocopies work and their degradation, look at this example:
+
+```js
+original:  'Santa Claus'
+1st copy:  'santa cla#s'
+2nd copy:  'sa#t# cl#+s'
+3rd copy:  'sa+## c#+:s'
+4th copy:  's#++. c+:.s'
+5th copy:  's#+:. c:. s'
+```
+
+Therefore `s#+:. c+:++` is a valid copy of `Santa Claus`. And, as you can see, the degradation of the letters does not occur in a specific order, it is random.
+
+Based on the CodeWars challenge Photocopy decay

2023/challenge-12/challenge-12.test.ts

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+import { describe } from 'vitest'
+import { checkIsValidCopy } from './challenge-12'
+
+const TEST_CASES: TestCases<[string, string], boolean> = [
+  { args: ['Santa Claus is coming', 'sa#ta cl#us is comin#'], expected: true },
+  { args: ['Santa Claus is coming', 'p#nt: cla#s #s c+min#'], expected: false },
+  { args: ['Santa Claus', ' Santa Claus '], expected: false },
+  { args: ['Santa Claus', '###:. c:+##'], expected: true },
+  { args: ['Santa Claus', 'sant##claus+'], expected: false },
+  { args: ['Santa Claus', 's#+:. c:. s'], expected: true },
+  { args: ['Santa Claus', 's#+:.#c:. s'], expected: false },
+  { args: ['Santa Claus', 'SantA ClauS'], expected: false },
+  { args: ['3 regalos', '3 .+:# #:'], expected: true },
+  { args: ['3 regalos', '3        '], expected: true },
+  { args: ['3 regalos 3', '3 .+:# #: 3'], expected: true },
+  {
+    args: [
+      'Santa Claus viene a buscarte para darte muchos regalos y eso es espectacular porque da mucha felicidad a todos los niños',
+      'Santa Claus viene a buscarte para darte muchos regalos y eso es espectacular porque da mucha felicidad a todos los niño',
+    ],
+    expected: false,
+  },
+]
+
+describe('Challenge #12: Is it a valid copy?', () => {
+  buildChallengeTestCases({
+    cases: TEST_CASES,
+    spreadFn: checkIsValidCopy,
+  })
+})

2023/challenge-12/challenge-12.ts

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+export function checkIsValidCopy(original: string, copy: string) {
+  let index = 0
+  let isValidCopy = true
+
+  for (const letter of original) {
+    const copyLetter = copy[index++]
+
+    const isValidLetter = [
+      letter.toLowerCase(),
+      '#',
+      '+',
+      ':',
+      '.',
+      ' ',
+    ].includes(copyLetter)
+
+    const isBlankSpace = +(letter === ' ')
+    const isValidCharacter = [isValidLetter, copyLetter === ' '][isBlankSpace]
+
+    isValidCopy = [isValidCopy, isValidCharacter][+isValidCopy]
+  }
+
+  return isValidCopy
+}

README.md

@@ -100,7 +100,7 @@ This repository contains the solutions to the challenges proposed by [@midudev](
 | 09  |        Switch the light        |       🟢       | [Show](https://adventjs.dev/challenges/2023/9)  | [Go](./2023/challenge-09/challenge-09.ts) |
 | 10  | Create your owm Christmas tree |       🟢       | [Show](https://adventjs.dev/challenges/2023/10) | [Go](./2023/challenge-10/challenge-10.ts) |
 | 11  |       The studious elves       |       🟠       | [Show](https://adventjs.dev/challenges/2023/11) | [Go](./2023/challenge-11/challenge-11.ts) |
-| 12  |               --               |       --       |                       --                        |                    --                     |
+| 12  |      Is it a valid copy?       |       🟠       | [Show](https://adventjs.dev/challenges/2023/12) | [Go](./2023/challenge-12/challenge-12.ts) |
 | 13  |               --               |       --       |                       --                        |                    --                     |
 | 14  |               --               |       --       |                       --                        |                    --                     |
 | 15  |               --               |       --       |                       --                        |                    --                     |