What is the size of the files you are typically working with?
How fast does it need to be?
How much memory does your system have?
You could (and should imho) have simplified the problem by making the files have only 2 "columns" each. That column one has 4 words in it doesn't matter, neither that there are numbers between column 1 and 2.
Re: 2 Hash Tables, 4 Keys...what to do?