Add Binary Search Tree exercise

[devkabiir]

This exercise:

• Focuses on implementation of a data structure using classes.
• explains how privacy (private properties and methods) works in dart.
• has resources and tips section in readme.md.
• has simple tests.

I left the config.json untouched on purpose.

[Stargator]

The Binary Search Tree specification doesn't have a canonical-data.json. In fact, there's a PR to include it.

We should follow Exercism precedence and wait until the json cases are implemented.

[Stargator]

Given comments in exercism/problem-specifications#555 (comment)

I think we should figure out how to order this. It's a complicated problem compared to the rest. I think we will need more exercises that can build up to this.

I'm fine with adding it, but we probably should be mindful of the varying difficulties and balance them out as much as we can.

[devkabiir]

@Stargator I've made a PR for adding the required canonical data but it's still open and needs opinions. I'd keep this PR open until that one is resolved. And then reorder the tests accordingly. Apart from tests I'd like your review on the implementation.

It's been a hectic week, it's Diwali season in India. Diwali is in 4 days there's all sorts of preparations pending. So my contributions will be slow this week.

[Stargator]

No worries. Thanks.

[devkabiir]

@Stargator Will start working on this one as soon as i get more time , this probably only needs updating tests, maybe a few changes in the example.dart and until config.json changes are figured out for this one. It'll probably be on standby.

[jvarness]

@Stargator @devkabiir does it make more sense to do other exercises first that involved data structures but are less complicated than binary trees?

Are there available exercises to implement that deal with like... Maps or Lists?

[Stargator]

@jvarness Probably, we may even already have some that could use List in the solution. But we haven't looked at specific ones that deal with those types explicitly in the problem.

Also, most of the proposed exercise implementations are not from some high-level plan, it's just whatever each person decided to spend time on. We could hold off on the binary tree implementations until we add a few more exercises that may make t easier for newcomers. We just have't had that discussion, yet. This PR could serve well in that regard.

If interested, this repo contains all the specifications for current exercises that can be applied to any track. Each exercise should have a defined specification before a track implements it.

[devkabiir]

This probably needs a full re-write (tests and example) as per updated canonical-json and all other major changes, I'll work on this probably next weekend.

[devkabiir]

Rewrote it compliant with the new canonical-data.json. I left config.json untouched on purpose. We should discuss the that.
@Stargator , @jvarness

[Stargator]

Looks good! Congratz @devkabiir It's been a long road for you on this!

For config.json:

    {
      "slug": "binary-search-tree",
      "uuid": "597f86bc-6717-4a4c-a2c6-58241ac3d6cb",
      "core": true,
      "unlocked_by": null,
      "difficulty": 5,
      "topics": [
        "inheritance",
        "classes",
"trees", "algorithms", "logic", "searching", "object_oriented_programming"
      ]
    }

@jvarness @devkabiir Note the topics, these are just what I choose from a look at the TOPICS.txt file. Feel free to discuss and bring up your own.

[devkabiir]

Need a little help here, Running pub run dart_style:format -l 120 -n . locally gives no output. Neither does pub run dart_style:format -l 120 -w . make any changes. Tired with dart 1.24.3 and dart 2.1. But the build seems to fail. Whats the issue?

[devkabiir]

Made a few notable changes:

1. Usage of null-aware operators
2. Updated code docs
3. Stricter types on BinarySearchTree and Node classes (removed dynamic)
4. Moved assert statements to constructor bodies. Keeping it in initializer seems to not work in dart 1.24.3
5. Added config.json entry, and added few more topics

I wanted to use Exceptions instead of asserts but thought that would be too many topics in a single exercise?

[Stargator]

@devkabiir From the root directory of the repo, I ran pub run dart_style:format -l 120 -n exercises/binary-search-tree/

And this is the response I got:
test/binary_search_tree_test.dart

I was using Dart 2.0, but 1.24.3 should work too. Though, Dart 1.24.3 didn't give me a response, must be due to differences in the SDK.

To answer your question, the issue seems to be that dart_style is not in binary_search_tree's pubspec.yaml. So use the main repo's and you should be good.

[Stargator]

Hey @devkabiir do you think you can complete this by April 30th? That's the deadline for the New Batch of Exercises milestone

[devkabiir]

Closed in #187