Leetcode_3_2:time_limit.rb

# @param {String} s
# @return {Integer}
def length_of_longest_substring(s)    
    max = 0

    for i in 0..s.length-1
        check = Array.new(256, false)
        for j in i..s.length-1
            index = s[j].ord
            if check[index] == false
                check[index] = true
            else
                break
            end
            
        end
        if check.count(true) > max      
            max = check.count(true)
        end
    end
    max
end