Feat: TwoSum function created with test cases (#1399)

* fix: #758  optimised armstrongNumber code

* fix:#758 Average Median code optimised

* feat: TwoSum function added with test cases

* revert code

* Fix: #758 used ternary operator to make code more optimised

* Feat: TwoSum function created with test cases

* Feat: TwoSum function created with test cases

* Resolved comments and changes requests

Maths/test/TwoSum.test.js

@@ -0,0 +1,28 @@
+import { TwoSum } from '../TwoSum.js'
+describe('Two Sum', () => {
+  const testCasesWithoutSolution = [
+    [[8], 8],
+    [[3, 3, 3, 3], 19]
+  ]
+  const testCasesWithSolution = [
+    [[2, 7, 11, 15], 9, [0, 1]],
+    [[15, 2, 11, 7], 13, [1, 2]],
+    [[2, 7, 11, 15], 17, [0, 3]],
+    [[7, 15, 11, 2], 18, [0, 2]],
+    [[2, 7, 11, 15], 26, [2, 3]]
+  ]
+
+  test.each(testCasesWithoutSolution)(
+    'Should return an empty array if there is no solution',
+    (nums, target) => {
+      expect(TwoSum(nums, target)).toEqual([])
+    }
+  )
+
+  test.each(testCasesWithSolution)(
+    'Should return the indices of two numbers that add up to the target',
+    (nums, target, expected) => {
+      expect(TwoSum(nums, target)).toEqual(expected)
+    }
+  )
+})