Backpack Coding Problem

Problem Statement

You are going on a hiking trip! It’s time to pack! Your backpack has a safe maximum weight capacity and you want to utilize all of its capacity. You have an assortment of different items you can pack. Assume you have an unlimited number of each item. The items you are considering packing weigh:

“itemsAvailable”:[ {“name” : “Bag of Apples”, “weight” : 5},
{“name” : “Bread”, “weight”: 1 },
{“name” : “Peanut Butter”, “weight”: 2},
{“name” : “Trail Mix”, “weight”: 3}]

You want to take at least one of each item with you, and use any remaining capacity to fit the least number of items as possible, while still using all capacity. For example, with a bag capacity of 27, you will want to have the following items:

• 4 Bags of Apples

• 1 Trail Mix

• 1 Peanut Butter

• 2 Bread

4x5 = 20

1x3 = 3

1x2 = 2

2x1 = 2

27 total capacity

Build a program that takes in a bag capacity and determines which items to put in your pack. Output your backpack contents.

Solution

I will briefly detail the structure of my solution.

Backpack.java

This file is the model object of the project and represents the concept of a backpack in the code. For this solution, I decided to let the backpack object to control it's own usage in order to ensure consistency. This file features two slightly different implementations of it's constructor to demonstrate how the solution might change to fit certain priorities. For the rest of the project, the assumption is made that additional complexity is not an issue and that the ability to dynamically handle a wider range of scenarios is more desirable.

Service.java

This file mimics the service layer of an application and is the place where the problem's main task is computed. Calling this function is how the project delivers results to the user for purposes of evaluating this solution. In a larger implementation of this project, the assumption is multiple different functions would live in this file, each serving as a solution to a business requirement.

Main.java

This file is a rough-and-ready implementation for demonstrating the correctness of the solution. A capacity and a list of items is fed to the main function and a result is printed to the terminal. Both can be changed at will. Running this file's main method will serve to allow you, the user, to run the solution.

TestCode.java

This file represents a test suite that would be present in the larger implementation. Present in this file are 4 JUnit tests covering the 3 examples outputs and a 4th edge case. Should you, the user, prefer, running these test cases will serve as proof of the solution's correctness.