Merge pull request #421 from sir-gon/feature/minimum_absolute_differe…

…nce_in_an_array

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

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`
+
+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/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.test.ts

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+import { describe, expect, it } from '@jest/globals';
+import { logger as console } from '../../../logger';
+
+import { minimumAbsoluteDifference } from './minimum_absolute_difference_in_an_array';
+
+import TEST_CASES from './minimum_absolute_difference_in_an_array.testcases.json';
+
+describe('minimum_absolute_difference_in_an_array', () => {
+  it('minimumAbsoluteDifference test cases', () => {
+    expect.assertions(3);
+
+    TEST_CASES.forEach((test) => {
+      const answer = minimumAbsoluteDifference(test.input);
+
+      console.debug(
+        `minimumAbsoluteDifference(${test.input}) solution found: ${answer}`
+      );
+
+      expect(answer).toStrictEqual(test.expected);
+    });
+  });
+});

src/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/hackerrank/interview_preparation_kit/greedy_algorithms/minimum_absolute_difference_in_an_array.ts

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+/**
+ * @link Problem definition [[docs/hackerrank/interview_preparation_kit/greedy_algorithms/minimum-absolute-difference-in-an-array.md]]
+ */
+
+export function minimumAbsoluteDifference(arr: number[]): number {
+  const sorted_nums = arr
+    .map((x: number): number => x)
+    .sort((a: number, b: number): number => b - a);
+
+  let result = Math.abs(sorted_nums[sorted_nums.length - 1] - sorted_nums[0]);
+
+  for (let i = 0; i < sorted_nums.length - 1; i++) {
+    const a_value = sorted_nums[i];
+    const b_value = sorted_nums[i + 1];
+
+    const diff = Math.abs(a_value - b_value);
+
+    result = Math.min(result, diff);
+  }
+
+  return result;
+}
+
+export default { minimumAbsoluteDifference };