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class Array def sum inject(0){|sum, x| sum + x} end def map_with_index! each_with_index{|e, idx| self[idx] = yield(e, idx)} end def map_with_index(&block) clone.map_with_index!(&block) end end class Player attr_accessor :games @@InitialRank = 100 def initialize @games = Array.new end def rank return @@InitialRank if games.empty? games[0,100].map_with_index{|game, index| (game[:rank] + (game[:won] ? 50 : -50)) * (150-index) }.sum / (150 - games[0,100].length/2) / games[0,100].length end def boundRank(otherRank) [[otherRank, rank+40].min, rank-40].max end def won(otherPlayer) if (games.empty? and otherPlayer.games.empty?) otherPlayer.games.unshift({:rank => @@InitialRank, :won => false}) games.unshift({:rank => @@InitialRank, :won => true}) elsif (games.empty?) games.unshift({:rank => boundRank(otherPlayer.rank), :won => true}) otherPlayer.games.unshift({:rank => otherPlayer.boundRank(rank), :won => false}) elsif (otherPlayer.games.empty?) otherPlayer.games.unshift({:rank => otherPlayer.boundRank(rank), :won => false}) games.unshift({:rank => boundRank(otherPlayer.rank), :won => true}) else otherRank = otherPlayer.rank otherPlayer.games.unshift({:rank => otherPlayer.boundRank(rank), :won => false}) games.unshift({:rank => boundRank(otherRank), :won => true}) end end end

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