Rectangles solution #373
Rectangles solution #373
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Hey wow!! Pharo > Finder blows me away again.
I wondered if there was a better way than... x flatCollect: [ :c | c ] but it was awkward entering the array twice, so I wondered if it could do variable assignment, and it can. Squeeze all this in the Examples textfield.
x := #(
'++'
'||'
'++') .
x flatCollect: [ :c | c ]
Discovered #concatenation
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| { #category : #'*Exercise@Rectangles' } | ||
| LineSegment >> points [ | ||
| ^self isHorizontal ifTrue: [ (self start y to: self end y) collect: [ :y | (self start x)@y ] ] ifFalse: [ (self start x to: self end x) collect: [ :x | x@(self start y )]] |
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Is this meant to be all on one line?
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I think github doesn't show formatting properly as this is actually formatted over several lines
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| { #category : #'*Exercise@Rectangles' } | ||
| LineSegment >> isHorizontal [ | ||
| ^self start x = self end x |
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this doesn't look like a boolean result (??) Typo 'minus' instead of 'equals' ?
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this is a boolean result - are the x values the same - however it did prompt me to change the name as horizontal ness is confusing if x@y are cartesian, where im actually using the point to represent row@column (so a bit of a stretch). I figure if the method is, isRow (and I used a comment) that makes it a bit better)
| indicesCollect: [ :r :c | | ||
| (matrix at: r at: c) = $+ | ||
| ifTrue: [ r @ c ] | ||
| ifFalse: [ nil ] ]) asArray reject: [ :p | p isNil ]. |
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This statement is long and hard to hold in my head. Could it be split... corners := corners reject: [...] ?
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I've refactored out a few sub methods, to make it more readable
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Brute force is quite a valid approach and is the only one I could think of for a while.
(not advocating you change yours, just sharing) |
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Your comment about generate line segment permutations is exactly what this solution is doing (maybe its a bit more obvious now) - it finds square permutations (based on the + corners), and then validates if they actually exist because they are correctly joined by "-" or "|" lines. (Probably worth saying this very text in the class comment actually) |
This is quite an interesting problem