Iterate once and only once through all the possible configurations of an array

Processing Coding Questions
5

to work out total combinations you need to understand what operations you are going to do. Say you are picking from a set value which can be reused then you would calculate x^y, x will be the number of choices you can make and y being the number of times you are allowed to make a choice. The number of choices remains the same as all probabilities are still available each time you choose. ( Think putting a card back into the deck, throwing a dice or flipping a coin).
If the choices cannot be reused then you would use the factorial to find out your max combinations, ie;

pick a card from a set of cards and then do not put your choice back in the deck.

52 total cards so 52! max combinations if you decide that you have t make 52 choices.

If you are making less than 52 choices then you have to amend the factorial calculation. We know that to calculate factorial we have to do
totalChoices * (maximumChoices - currentChoice) currentChoice
being the number of times we have already chosen. And finally we multiply our last answer with any new choices, giving us.

totalChoices * maxChoicesAllowed((maximumChoices - currentChoice) currentChoice)

then you can combine your knowledge of everything discussed to calculate the maximum allowed combinations for you current problem.

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