[Hacker Rank] Interview Preparation Kit: Dictionaries and Hashmaps: H…

algorithm-exercises-csharp-test/src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/RansomNote.Test.cs

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+namespace algorithm_exercises_csharp.hackerrank.interview_preparation_kit;
+
+[TestClass]
+public class RansomNoteTest
+{
+  public class RansomNoteTestCase
+  {
+    public string title = "";
+    public List<string> magazine = [];
+    public List<string> note = [];
+    public string expected = "";
+  }
+
+  public class ArraysLeftRotationsTestCase
+  {
+    public List<int> input = []; public int d; public List<int> expected = [];
+  }
+
+  private static readonly RansomNoteTestCase[] tests = [
+    new()
+    {
+      title = "Sample Test Case 0",
+      magazine = ["give", "me", "one", "grand", "today", "night"],
+      note = ["give", "one", "grand", "today"],
+      expected = "Yes"
+    },
+    new()
+    {
+      title = "Sample Test Case 1",
+      magazine = ["two", "times", "three", "is", "not", "four"],
+      note = ["two", "times", "two", "is", "four"],
+      expected = "No"
+    },
+    new()
+    {
+      title = "Sample Test",
+      magazine = ["two", "two", "times", "three", "is", "not", "four"],
+      note = ["two", "times", "two", "is", "four"],
+      expected = "Yes"
+    },
+  ];
+
+  [TestMethod]
+  public void testCheckMagazine()
+  {
+    string result;
+
+    foreach (RansomNoteTestCase test in tests)
+    {
+      result = RansomNote.checkMagazine(test.magazine, test.note);
+      Assert.AreEqual(test.expected, result);
+    }
+  }
+}

algorithm-exercises-csharp/src/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/RansomNote.cs

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+// @link Problem definition [[docs/hackerrank/interview_preparation_kit/dictionaries_and_hashmaps/ctci-ransom-note.md]]
+
+namespace algorithm_exercises_csharp.hackerrank.interview_preparation_kit;
+
+using System.Diagnostics.CodeAnalysis;
+using System.Collections.Generic;
+
+public class RansomNote
+{
+  [ExcludeFromCodeCoverage]
+  protected RansomNote() { }
+
+  private static readonly string __YES__ = "Yes";
+  private static readonly string __NO__ = "No";
+
+  public static bool checkMagazineCompute(List<string> magazine, List<string> note)
+  {
+    Dictionary<string, int?> dictionary = [];
+
+    foreach (string word in magazine)
+    {
+      if (dictionary.TryGetValue(word, out int? value))
+      {
+        dictionary[word] += 1;
+      }
+      else
+      {
+        dictionary[word] = 1;
+      }
+    }
+
+    foreach (string word in note)
+    {
+      if (dictionary.TryGetValue(word, out int? value) && value > 0)
+      {
+        dictionary[word] -= 1;
+      }
+      else
+      {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  public static string checkMagazine(List<string> magazine, List<string> note)
+  {
+    return checkMagazineCompute(magazine, note) ? __YES__ : __NO__;
+  }
+}

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`.