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/TwoSum.js

@@ -0,0 +1,24 @@
+/**
+ * Given an array of integers, find two numbers that add up to a specific target.
+ *
+ * @param {number[]} nums - The array of integers.
+ * @param {number} target - The target sum.
+ * @returns {number[]} - An array containing the indices of the two numbers.
+ *
+ * @example
+ * const nums = [2, 7, 11, 15];
+ * const target = 9;
+ * const result = twoSum(nums, target);
+ * // The function should return [0, 1] because nums[0] + nums[1] = 2 + 7 = 9.
+ */
+
+const TwoSum = (nums, target) => {
+  const numIndicesMap = new Map()
+  for (let i = 0; i < nums.length; i++) {
+    const complement = target - nums[i]
+    if (numIndicesMap.has(complement)) return [numIndicesMap.get(complement), i]
+    numIndicesMap.set(nums[i], i)
+  }
+  return []
+}
+export { TwoSum }

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)
+    }
+  )
+})