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Knapsack problem/Continuous: Difference between revisions
Added Elixir
m (→version 1: added/changed whitespace and comments, made the program safe from NOVALUE errors.) |
(Added Elixir) |
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Take all the greaves
Take 3.5kg welt</pre>
=={{header|Eiffel}}==
<lang Eiffel>
Line 714 ⟶ 715:
Take 3.5kg off welt.
The total value is 349.378
</pre>
=={{header|Elixir}}==
{{trans|Erlang}}
<lang elixir>defmodule KnapsackProblem do
def price_per_weight( items ), do: (for {name, weight, price} <-items, do: {name, weight, price / weight} )
def select( max_weight, items ) do
{_remains, selected_items} = List.foldr( List.keysort(items, 2), {max_weight, []}, &select_until/2 )
selected_items
end
def task( max_weight, items ) do
IO.puts "The robber takes the following to maximize the value"
for {name, weight} <- select( max_weight, price_per_weight(items) ), do: :io.fwrite("~.2f of ~s~n", [weight, name])
end
defp select_until( {name, weight, _price}, {remains, acc} ) when remains > 0 do
selected_weight = select_until_weight( weight, remains )
{remains - selected_weight, [{name, selected_weight} | acc]}
end
defp select_until( _item, acc ), do: acc
defp select_until_weight( weight, remains ) when weight < remains, do: weight
defp select_until_weight( _weight, remains ), do: remains
end
items = [ {"beef", 3.8, 36},
{"pork", 5.4, 43},
{"ham", 3.6, 90},
{"greaves", 2.4, 45},
{"flitch", 4.0, 30},
{"brawn", 2.5, 56},
{"welt", 3.7, 67},
{"salami", 3.0, 95},
{"sausage", 5.9, 98} ]
KnapsackProblem.task( 15, items )</lang>
{{out}}
<pre>
The robber takes the following to maximize the value
3.50 of welt
2.40 of greaves
2.50 of brawn
3.60 of ham
3.00 of salami
</pre>
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