You want to send your friend a package with different things.

Each thing you put inside the package has such parameters as index number, weight and cost. The package has a weight limit. Your goal is to determine which things to put into the package so that the total weight is less than or equal to the package limit and the total cost is as large as possible.

You would prefer to send a package which weighs less in case there is more than one package with the same price.

Your API should accept as its first argument a path to a filename. The input file contains several lines. Each line is one test case.

Each line contains the weight that the package can take (before the colon) and the list of items you need to choose. Each item is enclosed in parentheses where the 1st number is a item’s index number, the 2nd is its weight and the 3rd is its cost. E.g.

81 : (1,53.38,€45) (2,88.62,€98) (3,78.48,€3) (4,72.30,€76) (5,30.18,€9) (6,46.34,€48)
8 : (1,15.3,€34)
75 : (1,85.31,€29) (2,14.55,€74) (3,3.98,€16) (4,26.24,€55) (5,63.69,€52) (6,76.25,€75) (7,60.02,€74) (8,93.18,€35) (9,89.95,€78)
56 : (1,90.72,€13) (2,33.80,€40) (3,43.15,€10) (4,37.97,€16) (5,46.81,€36) (6,48.77,€79) (7,81.80,€45) (8,19.36,€79) (9,6.76,€64)

For each set of items that you put into a package provide a new row in the output string (items’ index numbers are separated by comma). E.g.

4
-
2,7
8,9

You should write a class com.arifng.packer.Packer with a static API method named pack. This method accepts the absolute path to a test file as a String. The test file will be in UTF-8 format. The pack method returns the solution as a String.

Your method should throw an com.arifng.exception.APIException if incorrect parameters are being passed. Therefore your signature should look like public static String pack(String filePath) throws APIException

Additional constraints:

1. Max weight that a package can take is ≤ 100
2. There might be up to 15 items you need to choose from
3. Max weight and cost of an item is ≤ 100

1. Java 11
2. Maven 3.6.3

1. mvn test

First, I read the file and convert it to objects - List<PackageOfThing> Then, choose things to construct package.

Facade pattern is used for mapping file to objects. PackagePopulator hide complexities of generating packages and its validation process from FileToPackageMapper.

The algorithm I used here is Dynamic programming. I can't use greedy here, because, I can't pick thing partially. So, I used DP.

• First, sort things of a package
• Then, construct maximum cost matrix with minimum weight
• Then, traverse matrix from last cell to find out which things need to include.

After finding all things in package (optimised things need to send in package) and generate result with indexes.

• I used List to store packages and things inside package, also for holding results
• Also used matrix (2D int array) for calculating the maximum cost with minimum weight

As this project will be used in other project, so I did not provided any main method to run. To check workflow, please run unit test.