validate_brackets_kel.rb

#this is the condensed version without explanations
def validate_brackets(s, valid = false)
    opening_brackets = ["{", "[", "(" ] 
    closing_brackets = {"}"=> "{", "]"=> "[", ")"=> "("} 
    brackets_arr = s.gsub(" ", "").split("")
    last_opened_type = []

    iterations = 0
    brackets_arr.each do |b|
        opening_brackets.include?(b) ? opened = true : closed = true
        if opened
            last_opened_type.push(b) 
        elsif closed 
            closing_brackets[b] == last_opened_type.last ? last_opened_type.pop() : break 
        end
        iterations +=1
    end
    valid = true if iterations == brackets_arr.size
    puts valid
end





# this is the long, more readable version with explanations
def validate_brackets(s)
    valid = false # by default this method returns false
    opening_brackets = ["{", "[", "(" ] # make an array of valid opening brackets
    closing_brackets = {"}"=> "{", "]"=> "[", ")"=> "("} # hash of valid closing bracket types and their corresponding open bracket pairs
    brackets_arr = s.gsub(" ", "").split("")
    
    last_opened_type = [] # store value of the last bracket that was opened but not closed

    iterations = 0
    brackets_arr.each do |b|
        # evaluate if the element is an opening or closing bracket
        opened = true if opening_brackets.include?(b) 
        closed = true if closing_brackets.keys.include?(b) 

        if opened
            last_opened_type.push(b) # if it is an opening bracket, push the value to the array of the last opened type array
        elsif closed 
            if closing_brackets[b] == last_opened_type.last # if its a closing bracket, validate that the element in the last opened array corresponds with the closing type ( ie. "}" should map to "{"" )
                last_opened_type.pop() # remove the last opened bracket type from the array, this essentially means it has been closed
            elsif closing_brackets[b] != last_opened_type.last # if the closing bracket does not correspond with the last opened bracket, this represents a faulty inpuy
                break
            end
        end
        iterations +=1 # keep count of iterations to determine if entire string was evaluated without error
    end
    valid = true if iterations == brackets_arr.size # make return value true if no rule breaking conditions were met
    puts valid
end