Respond to short response questions in clear, concise sentences directly within this file. Use markdown to ensure that your answers are formatted correctly.
Complete code challenges in exercises.js.
Use Test Driven Development to guide you. Run npm install to download dependencies. Run npm test to run tests locally. Ensure all tests are passing before submitting this problem set.
1. What is a Hash Map and how does it work? Be sure to mention the terms "hash key" and "hash function" in your explanation.
2. What are the benefits of using a Hash Map compared to using an Array? Be sure to mention the runtimes for retreival (getting a value given the key/index), insertion, and deletion.
Use a Hash Map to solve the following problems. Since Hash Maps are abstract data types, you can use any data structure (Arrays, Objects, Maps, etc.) to represent a Hash Map.
1. Given a non-empty array of numbers, every element appears twice except for one. Find that single number and return it. Implement a function singleNumber() with a linear runtime complexity.
Input: nums = [2,2,1]
Output: 1
Input: nums = [4,1,2,1,2]
Output: 4
2. Given an arbitrary ransom note string and another string containing all letters from a magazine, write a function that will return true if the ransom note string can be constructed from all the letters in the magazine; otherwise, it will return false. Each letter in the magazine string can only be used once in your ransom note. Implement a function canConstruct() with a linear runtime complexity.
Input: ransomNote = "a", magazine = "bcdefg"
Output: false
Explanation: Your ransom note requires an `a`, but the magazine does not contain an `a`.
Input: ransomNote = "aa", magazine = "abcdefg"
Output: false
Explanation: Your ransom note requires two `a`s, but the magazine does not contain enough `a`s.
Input: ransomNote = "aab", magazine = "aaabcdefg"
Output: true
Explanation: Your ransom note requires two `a`s and a `b`, and the magazine has at least two `a`s and at least one `b`.
3. You are given a list of products whose data is separated into three different arrays that hold the name, price, and weight of the product respectively. Consider the following arrays for example:
name = ["ball", "bat", "glove", "glove", "glove"]
price = [2, 3, 1, 2, 1]
weight = [2, 5, 1, 1, 1]
Our first product is a ball with a price of 2 and a weight of 2. The second product is a bat with a price of 3 and a weight of 5. Our third product is a glove with a price of 1 and a weight of 1. Our fourth product is a glove with a price of 2 and a weight of 1. Duplicate products contain identical parameters for all fields in the list (i.e. name, price, and weight). Write a function hasDuplicates() that returns true if there is a duplicate product, and returns false if every product is unique. Your solution should have linear runtime complexity.
Inputs:
name = ["ball", "bat", "glove", "glove", "glove"]
price = [2, 3, 1, 2, 1]
weight = [2, 5, 1, 1, 1]
Ouput: true
Explanation: The 3rd and 5th items are the same. Both have a name of "glove" with a price of 1 and weight of 1.
Inputs:
name = ["ball", "bat", "glove", "glove", "glove"]
price = [2, 3, 1, 2, 2]
weight = [2, 5, 1, 1, 2]
Ouput: false
Explanation: No two items have the same name, price, and weigth, so there are no duplicates.