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Simplify code using lists:usort, thanks to a tip from Ahmed Omar
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Andreas Pauley committed Mar 29, 2011
1 parent 9125147 commit f092e55
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2 changes: 1 addition & 1 deletion sudoku.erl
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Expand Up @@ -196,7 +196,7 @@ is_solved(Puzzle) ->
is_unit_solved(Puzzle, Unit) ->
UnitValues = flatmap(fun(S) -> values(Puzzle, S) end, Unit),
(length(UnitValues) == 9)
and (gb_sets:from_list(UnitValues) == gb_sets:from_list(?digits)).
and (lists:usort(UnitValues) == ?digits).

to_string(Puzzle) ->
{ValuesDict, _} = Puzzle,
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4 comments on commit f092e55

@kostis
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@kostis kostis commented on f092e55 Mar 29, 2011

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You probably also want to use =:= instead of == throughout.

@apauley
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Yes, I think read somewhere that =:= is more equal than == :-)
In comparisons like these, would you use =:= because it is more correct/better style, or because you would expect better performance?

@kostis
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@kostis kostis commented on f092e55 Mar 29, 2011

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Both, actually.
The use of =:= is more correct because the test will not accidentally succeed if a float somehow ends up there,
and you can expect slightly better performance because the compiler does not have to (generate code that) checks for floats.

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Cool:
faa8a31

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