Problem Ordering

[IanWhitney]

As brought up in #126 (and elsewhere), our problem ordering is weird. I've certainly put some problems in the wrong spots, for sure.

I ran through the example solutions for all of our problems made a table of what skills each problem (probably) requires. Implementations can vary, obviously.

problem	topics
hello-world	Some/None. Really? We did that in Hello World?
gigasecond	Crates, type stuff.
leap	Math, booleans
anagram	lifetimes, str vs string, loops, iter, vector
difference-of-squares	fold & map
allergies	struct, enum, bitwise (probably), vectors, filter
word-count	hashmap, str vs string, chars, entry api
hamming	result, chars, filter
rna-transcription	match, struct, str vs string
nucleotide-count	filter, entry api, mutablity, match
nucleotide-codons	struct, hash map, lifetimes, Result
scrabble-score	chaining map/fold. Hashmap (maybe)
roman-numerals	mutable, results, loops, struct, traits
robot-name	struct, slices, randomness, lifetimes, self mut
etl	btree?
raindrops	case (or formatting). Mutable string
bob	chars, string functions
grade-school	struct, entry api, Vec, Option
phone-number	option, format, unwrap_or, iters, match
hexadecimal	Option, zip/fold/chars, map
queen-attack	struct, trait (optional), Result
beer-song	case, vector (?), loop
sieve	vector, map, while let (optional)
minesweeper	board state, Vec, heavy logic
dominoes	I do not even know, man
parallel-letter-frequency	multi threading? heavy
sublist	enum, generic over type
custom-set	generic over type, vector, equality, struct
tournament	enum, file io, try!, result, hashmap, struct
rectangles	traits and structs, enum
forth	like, everything but lifetimes
circular-buffer	same

So, some stuff is at the bottom that clearly should be (rectangles, forth, circular-buffer). But the start of our problem list is not well geared towards newcomers. Let's discuss better options.

[IanWhitney]

And here's my first suggested order, grouped into sections just so I could explain why I put certain problems together:

Getting Started

This ordering feels pretty good to me. These problems tend to show up early in tracks and they don't seem to hit any of Rust's weirder edges.

problem	topics
hello-world	Some/None. Really? We did that in Hello World?
gigasecond	Crates, type stuff.
leap	Math, booleans
raindrops	case (or formatting). Mutable string
bob	chars, string functions
beer-song	case, vector (?), loop
difference-of-squares	fold & map

Getting into Rust

Now we start to hit some more Rust-specific stuff. And the order here I'm less clear on.

problem	topics
hamming	result
scrabble-score	chaining map/fold. Hashmap (maybe)
nucleotide-count	filter, entry api, mutablity, match
word-count	hashmap, str vs string, chars, entry api
etl	btree
sieve	vector, map, while let (optional)
rna-transcription	match, struct, str vs string
roman-numerals	mutable, results, loops, struct, traits
hexadecimal	Option, zip/fold/chars, map
grade-school	struct, entry api, Vec, Option
queen-attack	struct, trait (optional), Result
allergies	struct, enum, bitwise (probably), vectors, filter
sublist	enum, generic over type
phone-number	option, format, unwrap_or, iters, match
custom-set	generic over type, vector, equality, struct

Lifetimes

Now for the real Rust-specific stuff. We only have three exercises that require lifetimes. Anagrams is the easiest, since it doesn't use structs & randomness

problem	topics
anagram	lifetimes, str vs string, loops, iter, vector
nucleotide-codons	struct, hash map, lifetimes, Result
robot-name	struct, slices, randomness, lifetimes, self mut

Putting it all together

These are the ones where I looked at the example code and said "I dunno what this is even doing." I have no opinion about the order of these, since I don't fully understand them.

problem	topics
minesweeper	board state, Vec, heavy logic
dominoes	I do not even know, man
parallel-letter-frequency	multi threading? heavy
tournament	enum, file io, try!, result, hashmap, struct
rectangles	traits and structs, enum
forth	like, everything but lifetimes
circular-buffer	same

[kytrinyx]

@IanWhitney this is so good!

[IanWhitney]

I'm about to do a PR to add the Pangram exercise. My example implementation may not be the way most students go, so I'm not sure we can rely on it to figure out where the exercise should go.

But, most solutions will almost certainly use

• iterators
• Higher-order functions
• Sets

Based on that, I think it would go towards the start of the Getting Into Rust section. Somewhere in the first 3 problems.

[IanWhitney]

And #131, when it's ready for merge, should probably be in the 2nd half of Getting Into Rust. Somewhere around hexadecimal, I think.