A Common-Sense Guide to Data Structures and Algorithms in JavaScript, Volume 1

Exercises

The following exercises provide you with the opportunity to practice with hash tables. The solutions to these exercises are found in the section ​Chapter 8​.

1. Write a function that returns the intersection of two arrays. The intersection is a third array that contains all values contained within the first two arrays. For example, the intersection of [1, 2, 3, 4, 5] and [0, 2, 4, 6, 8] is [2, 4]. Your function should have a complexity of O(N). (If your programming language has a built-in way of doing this, don’t use it. The idea is to build the algorithm yourself.)

2. Write a function that accepts an array of strings and returns the first duplicate value it finds. For example, if the array is ["a", "b", "c", "d", "c", "e", "f"], the function ...