Bracket balance function

Bracket balance function

def brackets_balanced?(s)
	brackets = [['(',')'],['[',']'],['{','}']]
	flatten_brackets = brackets.flatten
	close_brackets = brackets.map{|e| e[1]}
	stack = ''
	for i in 0..s.size do
		stack += s[i] if flatten_brackets.include?(s[i])
		stack = stack[0,stack.size-2] if brackets.include? [stack[stack.size-2,1],stack[stack.size-1,1]]
		return false if close_brackets.include? stack[stack.size-1,1] 
	end
	stack.empty?
end
#TEST
puts brackets_balanced?('()(){}[]'*100000)
puts brackets_balanced?('(())'*100000)
puts brackets_balanced?(')')
puts brackets_balanced?('([]){}('*100000)
#etc