split_string_balanced.rb

# @param {String} s
# @return {Integer}
def balanced_string_split(s)
    counter = 0
    balance = 0
    characters = s.chars
    characters.each do |c|
        balance += 1 if c == 'L'
        balance -= 1 if c == 'R'
        counter += 1 if balance == 0
    end
    counter
end

Hint 1: Loop from left to right maintaining a balance variable when it gets an L increase it by one otherwise decrease it by one.
Hint 2: Whenever the balance variable reaches zero then we increase the answer by one.