I have a function that receives three different “people” objects and generates a new “compatibility” object based on the combined values in the “people” objects.
However, about 1/3 of the time the three “people” objects that it receives as input are the same as one before, though possibly in a different order. In these cases I do NOT want to make a new “score” object, but simply return a value contained within the existing object.
Originally, the program just loops through the list<> of “compatibility” objects searching for the one that belongs to these three “people” (since each “compatibility” object contains an array of people objects). This method is really slow considering that there’s over thousands of “compatibility” objects and over a million “people” objects.
I had the idea of using a dictionary where the key is a number I generated by combining the three people objects’ id values into a single UInt64 using XOR, and storing the score objects in as dictionary values rather than in a list. This cuts down the time by about half, and is acceptable in terms of time performance, but there’s way too many collisions, and it returns a wrong score too often.
Any suggestions or pointers would be much appreciated.
Edit: To add to the original question, each “people” object has a bunch of other fields that I could use, but the problem is making a key that is UNIQUE and COMMUTATIVE.
I think you’re looking at things in a much too complex manner. Take the 3 PersonID values and sort them,so that they’re always in the same order, no matter which order they were passed in. Then set a value in a hashtable using the three PersonIDs as the key, separated with a hyphen or some other character that won’t occur in a PersonID value. Then later, check if there’s a value in the hashtable with that key.
So if the three PersonIDs are 10, 5 and 22, the hash key could be something like “5-10-22”.