So I tried Wi2 with a coupon code from Bic Camera. Although it says DOUTOR cafes are covered, there are actually few wi-fi enabled DOUTORs even in Tokyo. Very disappointing. Let's see if it gets any better... Besides, the Wi2 site says DOUTOR in Hakozaki has a wi-fi spot, but I haven't been able to confirm that. I just walked by and didn't bother walking in though. It might work inside.
Today's self-study: I reviewed how adjacency matrices can be represented, and some about Floyd algorithm for finding shortest paths.