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The questions for Google Code Jam Qualifying round turned out to be simple. I was wondering why people could solve problem A so quickly, only to realise that I used an overkill solution for it (Trie). Problem B was a DFS and C DP.

I have been wanting to write about why we need theorem and why we should use them. The reason is because having theorems help us do less work. For example, to prove that dim(V/W) = dim(V) - dim(W), we can start with the basis and work to prove that the statement is correct. However, we can create a linear map T: V -> V/W, T(x) = x + W. Using dimension theorem, the above can be easily seen. The point I'm trying to make is that the extension of basis is already done in the dimension theorem, so by using dimension theorem, we can leave out that part of the proof.

AI allows me to play with a virgin set of mindstorm NXT for at least 10 weeks and I'm starting to panic about the project. I can really fill the weight of the work piling.