feat(data-structures/unstable): add BinarySearchTree methods ceiling, floor, higher, lower

[WWRS]

closes #3069

May break custom binary trees that reimplement BinarySearchTree.#findNode(). I think it's unlikely that anyone is doing that given that #findNode() should work on all child data structures of binary search trees. As pointed out, this is not a problem.

The new methods have the same time complexity as find().

[codecov]

Codecov Report

Attention: Patch coverage is 98.78049% with 1 line in your changes missing coverage. Please review.

Project coverage is 94.74%. Comparing base (096f0be) to head (1271a7a).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
data_structures/unstable_binary_search_tree.ts	98.78%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6544   +/-   ##
=======================================
  Coverage   94.74%   94.74%           
=======================================
  Files         583      584    +1     
  Lines       46478    46560   +82     
  Branches     6523     6539   +16     
=======================================
+ Hits        44036    44114   +78     
- Misses       2399     2402    +3     
- Partials       43       44    +1     

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[lionel-rowe]

May break custom binary trees that reimplement BinarySearchTree.#findNode()

It's not possible to reimplement #private methods in derived classes. Implementing a method with the same name in the derived class creates a new method that's only accessible within the derived class, rather than overriding the method in the parent.

class A {
    #private() {
        return 'A'
    }

    foo() {
        console.log(this.#private())
    }
}

class B extends A {
    #private() {
        return 'B'
    }

    bar() {
        console.log(this.#private())
    }
}

new A().foo() // logs 'A'
new B().foo() // still logs 'A'
new B().bar() // logs 'B'

[WWRS]

Ah, I see where I got confused. There's a change to an export in _binary_search_tree_internals and that gets used by RedBlackTree. I thought this meant RedBlackTree used some sort of extension of internals, but that's just exported to allow RedBlackTree access to those private methods. So the type change cannot cause any problems.

[kt3k]

@WWRS Sorry for the delay in review.

BinarySearchTree is part of stable API and we prefer to not mix stable features and unstable features.

Can you create an unstable version of BinarySearchTree in unstable_binary_search_tree.ts (probably by subclassing the stable one) and move the new methods there? (and also can you move the test cases of them in unstable_binary_search_tree_test.ts?)

[WWRS]

@kt3k Moved to unstable_binary_search_tree.ts 👍

[kt3k]

Thanks for updating!

LGTM