Running

$ go run cmd/validate/main.go

Backend Intern Challenge - Summer 2018

Problem

Different merchants have different products. Menus are a great way to present these products in an intuitive way to customers.

To address this we decided to build a system that allows Menus validation. Our system should be able to aggregate the provided Menus and identify if any of them contain cyclical references.

Nodes are expressed as objects in a JSON array with the following fields:

Fields	Possible Values	Optional Values	Description
`id`	`"number"`		Uniquely identifies each node of the Menu.
`data`	`"string"`		Specifies the data that the node holds.
`parent_id`	`"number"`	✓	Specifies the parent of the node.
`child_ids`	Array of `"number"`		Specifies the children of the node.

API Example Response

{
  "menus":[
    {
      "id":1,
      "data":"House",
      "child_ids":[3]
    },
    {
      "id":2,
      "data":"Company",
      "child_ids":[4]
    },
    {
      "id":3,
      "data":"Kitchen",
      "parent_id":1,
      "child_ids":[5]
    },
    {
      "id":4,
      "data":"Meeting Room",
      "parent_id":2,
      "child_ids":[6]
    },
    {
      "id":5,
      "data":"Sink",
      "parent_id":3,
      "child_ids":[1]
    },
    {
      "id":6,
      "data":"Chair",
      "parent_id":4,
      "child_ids":[]
    }
  ],
  "pagination":{
    "current_page":1,
    "per_page":5,
    "total":19
  }
}

API Response

The response will contain the followings keys:

menus - Array containing nodes that together become Menus.
pagination - An object containing the current_page, per_page and total keys

Instructions

Candidates can use any programming language of their choice.

Obtain a list of Nodes from the API and build the appropriate Menus. Cycles should be identified and the offending Menus should be marked as invalid. The max depth of a Menu is 4.

The output for the given example should be as follows:

{
  "valid_menus": [
    { "root_id": 2, "children": [4, 6] },
  ],
  "invalid_menus": [
    { "root_id": 1, "children": [1, 3, 5] }
  ]
}

The output is expected to be in JSON and to contain the following keys:

valid_menus - Array containing information about each valid menu:
- root_id - The id of the menu root
- children - An Array containing all the children belonging to the menu
invalid_menus - Array containing information about each invalid menu:
- root_id - The id of the menu root
- children - An Array containing all the children belonging to the menu

The API endpoint can be found at:

https://backend-challenge-summer-2018.herokuapp.com/challenges.json?id=1&page=1

This will return the first page of nodes. You can obtain subsequent pages by incrementing the page query parameter.

Extra Challenge

The same rules of the original challenge applies.

The API endpoint can be found at:

https://backend-challenge-summer-2018.herokuapp.com/challenges.json?id=2&page=1