introduction to Big O complexity and Regular expression

  We are introduced with the new idea of big O complexity (big Oh) and Regular expression (Regex) last week. The big O complexity gives an overview of the runtime complexity which I think they makes a lot sense in terms of the arithmetic proof. From what I've learned so far about regular expression, is that it is a bunch of characters that can include numbers, letters or operators, that forms a search pattern. The starnode, barnode and dotnode are some of the subnodes in a binary search tree. However, I am still confused with Regular expression thus I spent quite a lot of time on my assignment 2. I am not exactly sure if regular expression will appear on our future test, or exam as we weren't taught a lot of this topic, but I am sure that I will look more deeply in it.