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module Ch2 exposing ( .. )
import Array as A
import String as S
import Tuple as Tp
import List as L
import Maybe as Mb
combiIndex2 : Int -> List (Int, Int)
combiIndex2 n = L.concat
(L.map (\x1 ->
(L.map (\x2 -> (x1, x2) -- tuple is better choice
-- it was very hard to access
-- elements insdide
-- if a list maded
) (L.range (x1 + 1) n)))
(L.range 0 (n - 1)))
type alias Point = { col : Int, row : Int }
type alias HLine = { start : Int, end : Int, row : Int }
type alias Square = { hline : HLine, alsoAtRow : Int }
pointsAtRowsFromString : String -> Result String (List (List Point))
pointsAtRowsFromString input =
let linesStr = S.concat(S.lines input)
lines_ = S.split "]" linesStr
lines = L.take ((L.length lines_) - 1) lines_ -- ignore last garbage
-- matrixLines : a string at each row contains only '1' or '0'
matrixLines = L.filterMap
(\ln -> Just (S.filter
(\ch -> case ch of
'1' -> True
'0' -> True
_ -> False) ln))
lines
in if S.isEmpty (S.trim input) then
Err ""
else if L.length matrixLines < 2 then
Err "Number of Rows is too small: need at least 2 or more"
else Ok
(L.indexedMap
(\ri mln -> -- ri : row index
L.filterMap
(Mb.map
(\ci -> { col = ci, row = ri }))
(L.indexedMap
(\col ch -> if ch == '1'
then Just col else Nothing )
(S.toList mln)))
matrixLines)
getHorizLines : List (List Point) -> Result String (List HLine)
getHorizLines ptsAtRows =
let horizlines_
= L.concat -- flatten
(L.indexedMap
(\ri pts ->
L.map
(\cbi ->
Mb.map2
(\p1 p2 -> { start = p1.col
, end = p2.col
, row = ri} )
(A.get (Tp.first cbi) (A.fromList pts))
(A.get (Tp.second cbi) (A.fromList pts))
) (combiIndex2 (L.length pts))
) ptsAtRows)
in
Ok (L.filterMap identity horizlines_)
findSquares : List HLine -> Result String (List Square)
findSquares hlines =
let listLen = L.length hlines in
Ok (L.filterMap
identity
(L.filterMap
(\cbi ->
Mb.map2
(\hl1 hl2 ->
if hl1.start == hl2.start &&
hl1.end == hl2.end &&
(hl2.row - hl1.row) ==
(hl1.end - hl1.start) then
Just { hline = hl1, alsoAtRow = hl2.row }
else Nothing )
(A.get (Tp.first cbi) (A.fromList hlines)) -- type Maybe
(A.get (Tp.second cbi) (A.fromList hlines))) -- ditto
(combiIndex2 listLen)))
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