Define a method sum_to_n? which takes an array of integers and an additional integer, n, as arguments and returns true if any two elements in the array of integers sum to n. An empty array should sum to zero by definition.

gistfile1.rb

def sum_to_n?(arr, n)
	(arr.empty? && n.zero?) || arr.permutation(2).any? { |a, b| a + b == n }
end
# OR
def sum_to_n?(arr, n)
  return true if arr.empty? && n.zero?
  arr.combination(2).any? {|a, b| a + b == n }
end

puts "sum_to_n?([0,5,4,7,1], 10)"
puts sum_to_n?([0,5,4,7,1], 10)