From ebc9f922fe69625d44a6cddbe13878db527dccd2 Mon Sep 17 00:00:00 2001
From: iswilljr <iswilljr@gmail.com>
Date: Sun, 3 Dec 2023 09:49:06 -0500
Subject: [PATCH] feat(2023): add solution for challenge #03

---
 2023/challenge-03/README.md            | 27 ++++++++++++++++++++++++++
 2023/challenge-03/challenge-03.test.ts | 16 +++++++++++++++
 2023/challenge-03/challenge-03.ts      | 13 +++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 2023/challenge-03/README.md
 create mode 100644 2023/challenge-03/challenge-03.test.ts
 create mode 100644 2023/challenge-03/challenge-03.ts

diff --git a/2023/challenge-03/README.md b/2023/challenge-03/README.md
new file mode 100644
index 0000000..999a60c
--- /dev/null
+++ b/2023/challenge-03/README.md
@@ -0,0 +1,27 @@
+# Challenge #3: The naughty elf
+
+In Santa's workshop, **a mischievous elf** has been playing around with the gift production line, adding or removing an unplanned step.
+
+You have the original sequence of original manufacturing steps and the modified modified sequence that may include an extra step or be missing a step.
+
+Your task is to **write a function that identifies and returns the first extra step that was added or removed in the manufacturing chain**. If there is no difference between the sequences, return an empty string.
+
+```js
+const original = 'abcd'
+const modified = 'abcde'
+findNaughtyStep(original, modified) // 'e'
+
+const original = 'stepfor'
+const modified = 'stepor'
+findNaughtyStep(original, modified) // 'f'
+
+const original = 'abcde'
+const modified = 'abcde'
+findNaughtyStep(original, modified) // ''
+```
+
+Please, keep in mind:
+
+- **There will always be one different step or none.**
+- **The modification can occur anywhere in the string.**
+- **The original steps could be empty**
diff --git a/2023/challenge-03/challenge-03.test.ts b/2023/challenge-03/challenge-03.test.ts
new file mode 100644
index 0000000..5eb1404
--- /dev/null
+++ b/2023/challenge-03/challenge-03.test.ts
@@ -0,0 +1,16 @@
+import { describe } from 'vitest'
+import { findNaughtyStep } from './challenge-03'
+
+const TEST_CASES: TestCases<[string, string], string> = [
+  { args: ['abcd', 'abcde'], expected: 'e' },
+  { args: ['xxxx', 'xxoxx'], expected: 'o' },
+  { args: ['stepfor', 'stepor'], expected: 'f' },
+  { args: ['iiiii', 'iiiii'], expected: '' },
+]
+
+describe('Challenge #3: The naughty elf', () => {
+  buildChallengeTestCases({
+    cases: TEST_CASES,
+    spreadFn: findNaughtyStep,
+  })
+})
diff --git a/2023/challenge-03/challenge-03.ts b/2023/challenge-03/challenge-03.ts
new file mode 100644
index 0000000..e661155
--- /dev/null
+++ b/2023/challenge-03/challenge-03.ts
@@ -0,0 +1,13 @@
+export function findNaughtyStep(original: string, modified: string) {
+  const originalLen = original.length
+  const modifiedLen = modified.length
+
+  const sequences = {
+    [originalLen]: [original, modified],
+    [modifiedLen]: [modified, original],
+  }
+
+  const [steps, reference] = sequences[Math.max(originalLen, modifiedLen)]
+
+  return [...steps].find((step, index) => step !== reference[index]) ?? ''
+}