This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
I am not totally sure what it is you want here, but what ever it is, it sounds really expensive with an operation that will probably border on O(n^2) complexity. The larger your hashmap and the larger the collections contained within that hashmap, the longer it is going to take to process the probabilities.
Can you be a little more clear as to what you are trying to do?