Halloween 2026 Scheduling Challenge 🎃

This thread has picked up some discussion since I last looked!

My objective was to move the thinking from basic formulas towards the definition of compound data entities and associated operations, implemented as nested arrays and Lambda functions respectively ( I may address considerations such as efficiency later ).

=LET(
    n, SUM(ROUNDUP(Available / m, 0)),
    k, SEQUENCE(n),
    initialTreats, {HSTACK(Treat, Available)},
    initialList, {HSTACK("Treat", "Number")},
    initialState, HSTACK(initialTreats, initialList),
    results, REDUCE(initialState, k, DISTRIBUTEλ),
    return, TAKE(FLATTEN(results, "", 0), , -2),
    return
)

where the Lambda function is given by

DISTRIBUTEλ = LAMBDA(state▦, [_],                   // Beginning array of two nested arrays followed by a counter (unused)
    LET(
    //  Separate treat stack and record list
    //  Update Treats
        treats,    FLATTEN(INDEX(state▦,1,1)),      // An array showing both product names and counts
        item,       INDEX(treats,1,1),              // A scalar text string showing the next treat
        count,      INDEX(treats,1,2),              // A scalar numeric value showing its current count
        otherItems, DROP(treats, 1),                // A 2D array of treats
        remaining,  MAX(count - m, 0),              // A scalar value
        endTreats,  IF(remaining>0, VSTACK(otherItems, HSTACK(item, remaining)), otherItems),  // This is a 2D array
    //  Update List
        priorList, FLATTEN(INDEX(state▦,1,2)),  
        newList,   VSTACK(                          // This is the final record of an item and the remaining count
                        priorList, 
                        HSTACK(item, count - remaining)
                    ), 
    //  Combine to form end state
        endState▦,  HSTACK({endTreats}, {newList}), // This is to be an array of two nested arrays
        endState▦ 
    )
);

Now, of course, another approach occurs to me.  Instead of cycling the formulas each time a treat is given, I could cycle each time one runs through the entire treat basket!  

For me though, I am at the stage of attempting to develop techniques, so this has already been a useful excercise!