Merge pull request #1 from developerr-ayush/Feature-TwoSum-function

Feature two sum function

Author: developerr-ayush

Maths/TwoSum.js

@@ -0,0 +1,23 @@
+/*
+Given an array of integers, return indices of the two numbers such that they add up to
+a specific target.
+
+You may assume that each input would have exactly one solution, and you may not use the
+same element twice.
+
+Example
+Given nums = [2, 7, 11, 15], target = 9,
+Because nums[0] + nums[1] = 2 + 7 = 9, return [0, 1].
+return [0, 1].
+*/
+
+const TwoSum = (nums, target) => {
+  const numIndicesMap = {}
+  for (let i = 0; i < nums.length; i++) {
+    const complement = target - nums[i]
+    if (complement in numIndicesMap) return [numIndicesMap[complement], i]
+    numIndicesMap[nums[i]] = i
+  }
+  return []
+}
+export { TwoSum }

Maths/test/TwoSum.test.js

@@ -0,0 +1,18 @@
+import { TwoSum } from '../TwoSum.js'
+
+describe('Two Sum', () => {
+  it('Should find the indices of two numbers that add up to the target', () => {
+    expect(TwoSum([2, 7, 11, 15], 9)).toEqual([0, 1])
+    expect(TwoSum([15, 2, 11, 7], 13)).toEqual([1, 2])
+    expect(TwoSum([2, 7, 11, 15], 17)).toEqual([0, 3])
+    expect(TwoSum([7, 15, 11, 2], 18)).toEqual([0, 2])
+    expect(TwoSum([2, 7, 11, 15], 26)).toEqual([2, 3])
+    expect(TwoSum([2, 7, 11, 15], 8)).toEqual([])
+    expect(
+      TwoSum(
+        [...Array(10).keys()].map((i) => 3 * i),
+        19
+      )
+    ).toEqual([])
+  })
+})