Maximum Subarray Sum – Kadane’s Algorithm

def max_sub_arr(arr)
    max = 0
    max_last = 0
    arr.each do |i|
        max_last += i
        if max_last > max
            max = max_last
        end
        if max_last < 0
            max_last = 0
        end
    end
    return max
end

puts max_sub_arr([1,2,-4,-5,4,5,-1,-3,7,1,-2,-3,-5])