[somat]

It would be a more interesting challenge if the data file were larger than the memory. I would love to see what people would come up with on some baby vm with 512 mb of ram.

Even more interesting would be small ram, little local storage and a large file only available via network, I would like to see something other than http but realistically it would be http.

[pas]

As the file-memory ratio changes the problem becomes more and more stream processing, right? If the number of cities becomes too much to keep in memory then it becomes a database with "let's see who can find a better index data structure fitting for these I/O patterns and HW" game.

[anonymoushn]

For this problem, changing the file size to not fit in RAM doesn't really make the optimal solutions more interesting

[throwaway167]

Sixteen thousand Excel 97 spreadsheets?