[Hacker Rank] Interview Preparation Kit: Dictionaries and Hashmaps: Hash Tables: Ransom Note. Solved ✓.

Author: Gonzalo Diaz

docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md

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+# [Hash Tables: Ransom Notes](https://www.hackerrank.com/challenges/ctci-ransom-note)
+
+- Difficulty:  `#easy`
+- Category: `#ProblemSolvingIntermediate`
+
+Harold is a kidnapper who wrote a ransom note, but now he is worried it will be
+traced back to him through his handwriting. He found a magazine and wants to
+know if he can cut out whole words from it and use them to create an untraceable
+replica of his ransom note.
+The words in his note are case-sensitive and he must use only whole words
+available in the magazine.
+He cannot use substrings or concatenation to create the words he needs.
+
+Given the words in the magazine and the words in the ransom note,
+print `Yes` if he can replicate his ransom note exactly using whole words
+from the magazine; otherwise, print `No`.
+
+## Example
+
+`magazine` = "attack at dawn"  `note` = "Attack at dawn"
+
+The magazine has all the right words, but there is a case mismatch.
+The answer is `No`.
+
+## Function Description
+
+Complete the checkMagazine function in the editor below.
+It must print `Yes` if the note can be formed using the magazine, or .
+
+checkMagazine has the following parameters:
+
+- `string magazine[m]`: the words in the magazine
+- `string note[n]`: the words in the ransom note
+
+## Prints
+
+- string: either  or , no return value is expected
+
+## Input Format
+
+The first line contains two space-separated integers, `m` and `n`,
+the numbers of words in the  and the , respectively.
+
+The second line contains `m` space-separated strings, each `magazine[i]`.
+
+The third line contains `n` space-separated strings, each `node[i]`.
+
+## Constraints
+
+- $ 1 \leq m, n \leq 30000 $
+- $ 1 \leq $ length of `magazine[i]` and `note[i]` $ \leq 5 $
+- Each word consists of English alphabetic letters (i.e., `a` to `z` and `A` to `Z`).
+
+## Sample Input 0
+
+```text
+6 4
+give me one grand today night
+give one grand today
+```
+
+## Sample Output 0
+
+```text
+Yes
+```
+
+## Sample Input 1
+
+```text
+6 5
+two times three is not four
+two times two is four
+```
+
+## Sample Output 1
+
+```text
+No
+```
+
+## Explanation 1
+
+'two' only occurs once in the magazine.
+
+## Sample Input 2
+
+```text
+7 4
+ive got a lovely bunch of coconuts
+ive got some coconuts
+```
+
+## Sample Output 2
+
+```text
+No
+```
+
+## Explanation 2
+
+Harold's magazine is missing the word `some`.

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.js

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+/**
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md]]
+ */
+
+const __YES__ = 'Yes';
+const __NO__ = 'No';
+
+export function checkMagazineCompute(magazine, note) {
+  const dictionary = {};
+
+  for (const word of magazine) {
+    if (word in dictionary) {
+      dictionary[word] += 1;
+    } else {
+      dictionary[word] = 1;
+    }
+  }
+
+  for (const word of note) {
+    if (word in dictionary && dictionary[word] > 0) {
+      dictionary[word] -= 1;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+export function checkMagazine(magazine, note) {
+  return checkMagazineCompute(magazine, note) ? __YES__ : __NO__;
+}
+
+export default { checkMagazine };

src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.test.js

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger.js';
+
+import { checkMagazine } from './ctci-ransom-note.js';
+
+const TEST_CASES = [
+  {
+    title: 'Sample Test Case 0',
+    magazine: ['give', 'me', 'one', 'grand', 'today', 'night'],
+    note: ['give', 'one', 'grand', 'today'],
+    expected: 'Yes'
+  },
+  {
+    title: 'Sample Test Case 1',
+    magazine: ['two', 'times', 'three', 'is', 'not', 'four'],
+    note: ['two', 'times', 'two', 'is', 'four'],
+    expected: 'No'
+  },
+  {
+    title: 'Sample Test',
+    magazine: ['two', 'two', 'times', 'three', 'is', 'not', 'four'],
+    note: ['two', 'times', 'two', 'is', 'four'],
+    expected: 'Yes'
+  }
+];
+describe('ctci_ransom_note', () => {
+  it('checkMagazine test cases', () => {
+    expect.assertions(3);
+
+    TEST_CASES.forEach((value) => {
+      const answer = checkMagazine(value.magazine, value.note);
+
+      console.debug(
+        `checkMagazine(${value.magazine}, ${value.note}) solution found: ${answer}`
+      );
+
+      expect(answer).toStrictEqual(value.expected);
+    });
+  });
+});