Two sum

DIRECTORY.md

@@ -57,6 +57,7 @@
     * [LocalMaximomPoint](Data-Structures/Array/LocalMaximomPoint.js)
     * [NumberOfLocalMaximumPoints](Data-Structures/Array/NumberOfLocalMaximumPoints.js)
     * [QuickSelect](Data-Structures/Array/QuickSelect.js)
+    * [TwoSum](Data-Structures/Array/TwoSum.js)
   * **Graph**
     * [Graph](Data-Structures/Graph/Graph.js)
     * [Graph2](Data-Structures/Graph/Graph2.js)

Data-Structures/Array/TwoSum.js

@@ -0,0 +1,20 @@
+/**
+ * @function TwoSum
+ * @see https://leetcode.com/problems/two-sum/
+ * @description Given an array of integers, returns 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. This is a basic brute force approach.
+ * @param {Array} nums - array of integers.
+ * @param {number} target - target integer.
+ * @returns {Array} Array of the indices of the two numbers whose sum equals the target
+ * @example Given nums = [2, 7, 11, 15], target = 9; return [0, 1] because nums[0] + nums[1] = 2 + 7 = 9
+ * @complexity: O(n^2)
+ */
+const TwoSum = (nums, target) => {
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        return [i, j]
+      }
+    }
+  }
+}
+export { TwoSum }

Data-Structures/Array/test/TwoSum.test.js

@@ -0,0 +1,9 @@
+import { TwoSum } from '../TwoSum'
+
+test('TwoSum tests', () => {
+  expect(TwoSum([2, 7, 11, 15], 9)).toEqual([0, 1])
+  expect(TwoSum([2, 7, 11, 15, 6], 8)).toEqual([0, 4])
+  expect(TwoSum([1, 0, 5, 7, 3, 4], 6)).toEqual([0, 2])
+  expect(TwoSum([0, 8, 3, 1, 2, 7, 3], 6)).toEqual([2, 6])
+  expect(TwoSum([0, 5, 4, 2, 6, 7, 9, 1], 3)).toEqual([3, 7])
+})