Merge pull request #205 from sir-gon/feature/minimum-absolute-difference-in-an-array

[Hacker Rank] Interview Preparation Kit: Greedy Algorithms: Minimum A…

Author: sir-gon

docs/hackerrank/interview_preparation_kit/greedy_algorithms/minimum-absolute-difference-in-an-array.md

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+# [Minimum Absolute Difference in an Array](https://www.hackerrank.com/challenges/minimum-absolute-difference-in-an-array)
+
+- Difficulty:  `#medium`
+- Category: `#ProblemSolvingBasic` `#greedyalgorithms`
+
+The absolute difference is the positive difference between two
+values `a` and `b`, is written $ \lvert a - b \rvert $
+or $ \lvert b - a \rvert $
+and they are equal. If `a = 3` and `b = 2`, $ \lvert 3 - 2 \rvert =
+\lvert 2 - 3 \rvert = 1 $.
+Given an array of integers, find the minimum absolute difference
+between any two elements in the array.
+
+**Example** `arr = [-2, 2, 4]`6
+
+There are  pairs of numbers: `[-2, 2]`, `[-2, 4]` and `[2, 4]`.
+The absolute differences for these pairs are
+$ \lvert (-2) - 2 \rvert = 4 $, $ \lvert (-2) - 4 \rvert = 6 $ and
+$ \lvert 2 - 4 \rvert = 2 $.
+The minimum absolute difference is `2`.
+
+## Function Description
+
+Complete the minimumAbsoluteDifference function in the editor below.
+It should return an integer that represents the minimum absolute difference
+between any pair of elements.
+
+minimumAbsoluteDifference has the following parameter(s):
+
+- `int arr[n]`: an array of integers
+
+## Returns
+
+int: the minimum absolute difference found
+
+## Input Format
+
+The first line contains a single integer , the size of .
+The second line contains  space-separated integers, .
+
+## Constraints
+
+- $ 2 \leq n \leq 10^5 $
+- $ -10^9 \leq arr[i] \leq 10^9 $
+
+## Sample Input 0
+
+```text
+3
+3 -7 0
+```
+
+## Sample Output 0
+
+```text
+3
+```
+
+## Explanation 0
+
+The first line of input is the number of array elements. The array,
+ `arr = [3, -7, 0]`
+There are three pairs to test: `(3, -7)`, `(3, 0)`, and `(-7, 0)`.
+The absolute differences are:
+
+- $ \lvert 3 - -7 \rvert => 10 $
+- $ \lvert 3 - 0 \rvert => 3 $
+- $ \lvert -7 - 0 \rvert => 7 $
+
+Remember that the order of values in
+the subtraction does not influence the result.
+The smallest of these absolute differences is `3`.
+
+## Sample Input 1
+
+```text
+10
+-59 -36 -13 1 -53 -92 -2 -96 -54 75
+```
+
+## Sample Output 1
+
+```text
+1
+```
+
+## Explanation 1
+
+The smallest absolute difference is $ \lvert - 54 - -53 \rvert = 1$.
+
+## Sample Input 2
+
+```text
+5
+1 -3 71 68 17
+```
+
+## Sample Output 2
+
+```text
+3
+```
+
+## Explanation 2
+
+The minimum absolute difference is $ \lvert - 71 - 68 \rvert = 3$.

src/algorithm_exercises_csharp/hackerrank/interview_preparation_kit/greedy_algorithms/MinimumAbsoluteDifferenceInAnArray.cs

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+// @link Problem definition [[docs/hackerrank/interview_preparation_kit/greedy_algorithms/minimum-absolute-difference-in-an-array.md]]
+
+namespace algorithm_exercises_csharp.hackerrank.interview_preparation_kit.greedy_algorithms;
+
+using System.Diagnostics.CodeAnalysis;
+
+public class MinimumAbsoluteDifferenceInAnArray
+{
+  [ExcludeFromCodeCoverage]
+  private MinimumAbsoluteDifferenceInAnArray()
+  {
+  }
+
+  /**
+   * minimumAbsoluteDifference.
+   */
+  public static int minimumAbsoluteDifference(List<int> arr)
+  {
+    List<int> sortedNums = [.. arr.ConvertAll(x => x).OrderBy(x => x).ToList()];
+
+    // Find the minimum absolute difference
+    int result = 0;
+    bool resultEmpty = true;
+
+    for (int i = 0; i < sortedNums.Count - 1; i++)
+    {
+      int aValue = sortedNums[i];
+      int bValue = sortedNums[i + 1];
+
+      int diff = Math.Abs(aValue - bValue);
+
+      if (resultEmpty)
+      {
+        result = diff;
+        resultEmpty = false;
+      }
+      else
+      {
+        result = Math.Min(result, diff);
+      }
+    }
+
+    return result;
+  }
+}

src/algorithm_exercises_csharp_test/Resources/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.testcases.json

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+[
+  {
+    "title": "Sample Test case 0",
+    "input": [3, -7, 0],
+    "expected": 3
+  },
+  {
+    "title": "Sample Test case 1",
+    "input": [-59, -36, -13, 1, -53, -92, -2, -96, -54, 75],
+    "expected": 1
+  },
+  {
+    "title": "Sample Test case 2",
+    "input": [1, -3, 71, 68, 17],
+    "expected": 3
+  }
+]

src/algorithm_exercises_csharp_test/hackerrank/interview_preparation_kit/greedy_algorithms/MinimumAbsoluteDifferenceInAnArray.Test.cs

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+namespace algorithm_exercises_csharp_test.hackerrank.interview_preparation_kit.greedy_algorithms;
+using algorithm_exercises_csharp_test.lib;
+using algorithm_exercises_csharp.hackerrank.interview_preparation_kit.greedy_algorithms;
+
+[TestClass]
+public class MinimumAbsoluteDifferenceInAnArrayTest
+{
+  public class MinimumAbsoluteDifferenceInAnArrayTestCase
+  {
+    public string title = "";
+    public List<int> input = [];
+    public int expected;
+  }
+
+  private List<MinimumAbsoluteDifferenceInAnArrayTestCase> testCases { get; set; } = default!;
+
+  [TestInitialize]
+  public void testInitialize()
+  {
+    testCases = JsonLoader.resourceLoad<List<MinimumAbsoluteDifferenceInAnArrayTestCase>>(
+      "hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.testcases.json"
+    ) ?? [];
+  }
+
+  [TestMethod]
+  public void testMinimumAbsoluteDifferenceInAnArray()
+  {
+    int result;
+
+    foreach (MinimumAbsoluteDifferenceInAnArrayTestCase test in testCases)
+    {
+      result = MinimumAbsoluteDifferenceInAnArray.minimumAbsoluteDifference(test.input);
+      Assert.AreEqual(
+        test.expected,
+        result,
+        String.Format(
+          "minimumAbsoluteDifference({0}) => must be: {1}",
+          test.input.ToString(),
+          test.expected
+        )
+      );
+    }
+  }
+}