Best combination based in rules [closed] - ruby

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Which combination of five entries has the largest combined scores subject to the condition?

Answer 1

If the dataset is not huge, here you go (possibly quite inefficient):
data =
%|Derek Aufderhar, 2134, 1
Hadley Kuhn, 2044, 0
Myrtie Lueilwitz, 2207, 2
Mitchell Schiller, 2036, 2
Javier Walter MD, 2485, 4
Waino Leuschke, 2486, 2
Ariel Jacobson, 2015, 3
Melvin Bailey, 2485, 0
Dovie Emmerich, 2383, 4
Adrian Stroman Jr., 2180, 1
Helen Douglas, 2352, 4
Yessenia O’Reilly, 2247, 2|
# unnecessary: transform to hash for clarity
values =
data.
split($/).
map { |e| e.split(',') }.
map { |name, elo, score| {name: name, elo: elo.to_i, score: score.to_i } }
# find the top
values.
combination(5).
reject { |data| data.map { |e| e[:elo] }.inject(:+) > 11_000 }.
max { |data| data.map { |e| e[:score] }.inject(:+) }
#⇒ [{:name=>"Yessenia O'Reilly", :elo=>2247, :score=>2},
# {:name=>"Helen Douglas", :elo=>2352, :score=>4},
# {:name=>"Adrian Stroman Jr.", :elo=>2180, :score=>1},
# {:name=>"Ariel Jacobson", :elo=>2015, :score=>3},
# {:name=>"Mitchell Schiller", :elo=>2036, :score=>2}]

Answer 2

Code
def best_five(players, max_elo)
players.combination(5).with_object({ names:[], tot_scores: -1 }) do |arr, best|
names, elos, scores = arr.map(&:values).transpose
best.replace({ names: names, tot_scores: scores.sum }) unless
elos.sum > max_elo || scores.sum <= best[:tot_scores]
end
end
Here players is an array of hashes, each with keys :name, :elo and score, where the value of :name is a string and values of the other two keys are integers.
Example
players =<<_
Derek Aufderhar, 2134, 1
Hadley Kuhn, 2044, 0
Myrtie Lueilwitz, 2207, 2
Mitchell Schiller, 2036, 2
Javier Walter MD, 2485, 4
Waino Leuschke, 2486, 2
Ariel Jacobson, 2015, 3
Melvin Bailey, 2485, 0
Dovie Emmerich, 2383, 4
Adrian Stroman Jr., 2180, 1
Helen Douglas, 2352, 4
Yessenia O’Reilly, 2247, 2
_
It is convenient to convert this string to a hash, both to address the current problem and to perform other operations with the data.
players_by_name = players.each_line.with_object({}) do |line, h|
name, elo, score = line.split(',')
h[name] = { name: name, elo: elo.to_i, score: score.to_i }
end
#=> {"Derek Aufderhar" =>{:name=>"Derek Aufderhar", :elo=>2134, :score=>1},
# "Hadley Kuhn" =>{:name=>"Hadley Kuhn", :elo=>2044, :score=>0},
# ...
# "Yessenia O’Reilly"=>{:name=>"Yessenia O’Reilly", :elo=>2247, :score=>2}}
We may now compute the best five for max_elo = 11000:
best = best_five(players_by_name.values, 11000)
#=> {:names=>["Myrtie Lueilwitz", "Mitchell Schiller", "Ariel Jacobson",
# "Dovie Emmerich", "Helen Douglas"],
# :tot_scores=>15}
To retrieve information for these five players we compute the following:
a = players_by_name.values_at(*best[:names])
#=> [{:name=>"Myrtie Lueilwitz" , :elo=>2207, :score=>2},
# {:name=>"Mitchell Schiller", :elo=>2036, :score=>2},
# {:name=>"Ariel Jacobson" , :elo=>2015, :score=>3},
# {:name=>"Dovie Emmerich" , :elo=>2383, :score=>4},
# {:name=>"Helen Douglas" , :elo=>2352, :score=>4}]
We already know the scores sum to 15. As
a.map { |h| h[:elo] }.sum
#=> 10993
we see that the combined ELO limit is not exceeded.
Array#sum made its debut in Ruby v2.4.