length_of_longest_substring.rb

# @param {String} s
# @return {Integer}
def length_of_longest_substring(s)
  hash=Hash.new()
  hash["firstchar"]=0
  i=0
  array=Array.new()
  s.chars.map do |char|
    if hash[char]!=nil and hash[char]>=hash["firstchar"]
      array<<(i-hash["firstchar"])
      hash["firstchar"]=hash[char]+1
    end
    hash[char]=i
    i+=1
  end
  array<<(i-hash["firstchar"])
  array.sort.last
end