Most Efficient Way to Loop Through Columns of Identical Data - Without Duplicates - excel

Question

I have coded something to evaluate the result of every possible combination of inputs, in hopes to optimize a solution.
I have three identical columns of inputs, and my loop cycles through them all in search of the best combinations of inputs to yield the highest output. Example:
475,475,475
391,391,391
24,24,24
999,999,999
Duplicates are not allowed. I have been able to error correct for this per iteration, but not iteration v. iteration. As an example the first result I evaluate is 475 391 24.
QUESTION: The order of the inputs have no impact on the result I am evaluating. My dataset is so large, it is time consuming to evaluate 475 391 24 and then later again evaluate 391 475 24, and then again evaluate 24 391 475. Is there aa way to design around this? I am unable to manipulate the the source data. I have only a modest VBA skillset, but even the basic concept of solving this problem would be helpful. I imagine this is a common problem in many programming languages.

Answer 1

A possible solution would be to use a dictionary in some way: whenever you read the 3 values, sort them, put them in a CSV string in ascending order, then lookup in the dictionary.
It is hard to tell for sure if this will accelerate your code, because you need to make sure if your evaluation function is more or less expensive than the operation of sorting and dictionary lookup.
Another possibility is to remove duplicates from your data after doing some tranformation on it. Suppose your data is in columns A, B and C. Generate data into D, E and F with formulas in the following way:
the first column holds the min: Di--> =min(Ai:Ci)
the third column is the max: Fi --> =max(Ai, Ci))
the second column is the middle Ei--> =sum(Ai:Ci) - Di - Fi)
after then, select the range in D,E,F, copy and paste it as values, Remove Duplicates, and finally, apply your procedure on the remaining data.

Answer 2

If the order of inputs has no impact, you could first sort the lists. Then choose an item from the first column, an item from the second column that is greater the the first item, and an item from the third that is greater than the second. This assures that each combination is tried only once, not 6 times (so a ~6X speedup if the initial sort not too burdensome).