coin change

coin_change.rb

def coin_change(amount, denominations, partial_acc = [], acc = [])
  denominations.each { |e|
    acc.push(partial_acc.sort) if amount == 0
    if amount - e >= 0
      immutable_partial_acc = partial_acc.dup.push(e)
      coin_change(amount - e, denominations, immutable_partial_acc, acc)
    end
  }
  return acc.uniq
end