I am trying to retrieve the biggest number in a Linked List containing only integers.
If the list contains: 2, 67, 3, 9.
I want to return 67.
I'm having trouble visualizing and coming up with code that does this. Even a pseudo code would help.
Edit: I'm using Java to do this.
Note that:
You need to traverse the whole list; you don't know in advance where the maximum is going to be.
You'll need to carry some state while traversing: at any point, it may be the case that the rest of the list does not contain the maximum, and so you'll need to hang on to your current understanding of what it is.
So the general form of the pseudo-code will look like this:
Initialise the state that represents the maximum.
For each element in the list in turn: update the state, based on the element.
Lastly, you'll need to handle the edge cases: what does it mean to find the maximum of an empty Linked List?
To be more specific:
If the list is empty, return an error condition.
Let m, representing the current idea of the maximum, be the first element of the list.
For each remaining element of the list, if it is greater than m, set m to be the element.
At each point in the iteration, you have the invariant that m is the largest number so far in the list. When you are done, it must therefore be the largest number in the whole list.
Related
I’m trying to make a formula that accomplishes this:
From a list of numbers, find the pairs of numbers with the lowest difference and second lowest difference, and write their differences elsewhere(I don’t know how to do this)
Use those numbers to find and use the value(a name)of the cell to their left(I don’t know how to do this with duplicate numbers)
How would I go about this?
The final product should include all 4 numbers, names, and both differences.
In the picture below, the pink shaded section is the goal.
What I did is to first SORT the values:
=SORT(A2:B,2,1)
Then, wrapped it in LAMBDA (in order not to repeat those formula again and again), and started "scanning" those values to find the differences. Since it's already sorted, the "smallest" will be found in this comparison.
For this, I used MAP. Used SEQUENCE, COUNTA and INDEX in order to find the amount of values in the first column; and SEQUENCE will help me do the "navigation". With the variable resultant "p" I searched each row with the next one (p+1). Resulting in something like this:
=LAMBDA(sorted,MAP(SEQUENCE(COUNTA(INDEX(sorted,,1))-1),LAMBDA(p,{INDEX(sorted,p,1),INDEX(sorted,p+1,1),INDEX(sorted,p+1,2)-INDEX(sorted,p,2)})))(SORT(A2:B,2,1))
With that, you're already one step away. Just with SORTN you can find the four smallest differences:
=LAMBDA(diff,SORTN(diff,4,1,3,1))
(LAMBDA(sorted,MAP(SEQUENCE(COUNTA(INDEX(sorted,,1))-1),LAMBDA(p,{INDEX(sorted,p,1),INDEX(sorted,p+1,1),INDEX(sorted,p+1,2)-INDEX(sorted,p,2)})))
(SORT(A2:B,2,1)))
I hope it's already useful! You can split those values in two columns, obviously; just using INDEX to access the desired row of this formula; or just locate the formula somewhere and refer to those cells. Let me know if it's useful!
you can try:
=LAMBDA(z,SORTN(MAP(INDEX(z,,1),INDEX(z,,2),LAMBDA(a,b,{a,b,ABS(XLOOKUP(a,A:A,B:B,)-XLOOKUP(b,A:A,B:B,))})),4,0,3,1))(INDEX(SPLIT(QUERY(UNIQUE(MAP(LAMBDA(z,FLATTEN(z& "🐠" &TRANSPOSE(z)))(FILTER(A2:A, A2:A<>"")),LAMBDA(y,JOIN("🐠",SORT(UNIQUE(TRANSPOSE(SPLIT(y,"🐠")))))))),"Select Col1 Where Col1 CONTAINS '🐠'"),"🐠")))
In a sheet made of names and scores, I am trying to build a sheet to display the name of the people with the best scores.
To do so:
I sort the scores
I get the index of the biggest value
I offset the names list with the given index
When I want to get the second biggest value, I only have to get the index of the second biggest value on step 2.
There is a problem if two values are tied for the biggest, as MATCH() will always give me the index of the first value found.
I thought of determining the index of the biggest value, then excluding this index from the range used to determine the second biggest value, but I could not achieve it as the range lengths may be different.
I also thought of using a function or script that returns the Nth index that meets a criteria from a range, but I did not find anything to do so.
Image
Here is an example spreadsheet
https://docs.google.com/spreadsheets/d/1RrUpAjbMBze9L5OqxdyEWBnYXq98LtohdgROF8s68FI/edit?usp=sharing
One way is to add a column number and sort on that as well as on the score, then take the second element in the list:
=ArrayFormula(index(sort(transpose({B1:F3;column(B1:F3)}),3,false,4,true),2,1))
Note that the headers (players' names) are sorted along with their scores.
EDIT
Actually Sort in GS is a stable sort (in other words, according to the documentation 'range is sorted only by the specified columns, other columns are returned in the order they originally appear') so this is sufficient:
=ArrayFormula(index(sort(transpose(B1:F3),3,false),2,1))
I'm setting up a Google Sheet that will calculate the most effective purchase size of specific agricultural inputs (fertilizer, chemical, etc). I set up the price data in its own tab with a separate row for each input name + size.
To keep it easy for the user I'd like to require only the input name, # of gallons per acre, and acres and then have a formula spit out the total cost and most effective purchase (bulk if > X gallons, X # of 250 gallon containers + X 55 drums, etc). How can I use the input name plus a wildcard to find the appropriate purchase size?
https://docs.google.com/spreadsheets/d/1bMOPuk2qhmVuJT7vE_ni3KFxfcgKvwTwkM4p50xQF_0/edit?usp=sharing
I tried:
=ArrayFormula(iferror(INDEX('Data (Current)'!H2:H,SMALL(IF($A2&"*"='Data (Current)'!A2:A,ROW('Data (Current)'!A2:A)-1),1))))
...but it returns blank so I'm guessing the reference $A2&"*" to the input name isn't working properly. When I replace it with a string found in the 'Data (Current)' tab then it works fine.
=ArrayFormula(iferror(INDEX('Data (Current)'!H2:H,SMALL(IF($A2&"*"='Data (Current)'!A2:A,ROW('Data (Current)'!A2:A)-1),1))))
I expected the output to be the smallest value (in this case I think it's 5). Then when I change the last number to 2 or 3 it will find the next smallest value, in this case, 55 or 250. Then I can use simple formulas to interact with that and finish the spreadsheet.
Unfortunately, the actual output is nothing, or "".
Sorry if this isn't what you're looking for, as I had some trouble understanding your question.
Presuming what you want is essentially this:
I want to buy Y quantity of item.
I can buy item at cheaper prices if I buy in higher quantities, although sometimes they have a minimum order quantity.
What is the most optimal combination of the options I have to minimize the price I pay?
I'm unsure if there's a simple solution for this within Google Sheets alone. This might be treading more into Apps Script territory.
However, that's not to say that it's not impossible. I've "brute-forced" the above solution above with an iterative-like approach, for the "Chelated Calcium" product: https://docs.google.com/spreadsheets/d/1YSBiSx0IMr4T0R11Dqb-tqOhH4AOTTAWeH2yQfT4X5w
First, list the data in a standardized manner. This includes giving each same product something easy to look it up by. For example, on the Data (Current) tab, I've added 3 columns:
Product Common Name - This is used so that all items of different quantities can be found easily, without needing wildcards.
Gallons - Much easier to parse the data if it it's explicitly laid out.
Minimum Order Gallons - This is your threshold for Bulk. I've set it at an arbitrary 20,000 gallons for Chelated Calcium.
The data here is ordered least-effective first. How you do this will be up to you. In this case, I sorted by the Retail Cost Per Ounce parameter from your sheet, highest first. This eliminates any guesswork about which of the options are most effective, since you can just traverse your options in order. Note: The way I've laid out the formulas will only work IFF the same products are directly next to each other. It won't work if there are other products between them.
On the Field Level Tool tab, standardize your inputs to the Gallons unit. I do this in Total Gallons Needed column (I multiply anything with a "GAL" with 1, and "QUART" with 0.25).
For each item, determine the row numbers where the product begins and ends. This is marked by columns L (Least Efficient Index) and M (Most Efficient Index). I got these results by using the MATCH function.
Set up the iterations, from 0 to N-1. On this sheet, I've set up N=5 iterations, which means that it can traverse 5 different options of the same product only. Since Chelated Calcium only has 4 different options (5 Gal, 30 Gal, 250 Gal, Bulk), 5 is more than enough for this product. If you have products with more options, you may want to have more iterations.
The iterations are on the right side of the Field Level Tool tab.
In your case, you might want to put it on a different tab since the place I put it makes the file look very messy.
In each iteration, I perform the following steps:
To Fulfill - How many gallons still need to be purchased by this iteration?
ThisIndex - What is the row number of this iteration? This is determined by Most Efficient Index - Iteration Number. Remember that since we sorted in order of ascending efficiency, this means that the iteration starts with the most efficient option it can find first. There is a check to make sure that it only outputs a value if it is between the range [Least Efficient Index, Most Efficient Index]. Otherwise, it will be blank to avoid miscalculations by intruding into another product in the Data (Current) tab.
Retail Price, Minimum Gals, Gallons per Order - Simple data extraction for easy usage in the iteration, using INDEX (and indirectly, MATCH by virtue of ThisIndex).
Order - This formula does a couple of things, outlined below:
It checks whether there still remains a valid choice of product at this iteration. It does this by checking whether ThisIndex still exists. If the product doesn't exist, then it will be nulled. This is accomplished by using the IF function.
It will determine if there is a minimum threshold that must be met to purchase this choice. You can see in the 0th iteration, for example, that there is a minimum quantity of 20,000 gallons. If To Fulfill quantity is greater than or equal to the threshold OR there is no threshold, then a purchase is quantified by this column. The mathematics are simply to divide the To Fulfill amount by the Gallons per Order amount to determine the number of orders of this particular product choice. If there is a threshold but the To Fulfill amount doesn't meet it, then this iteration is skipped with a 0 order value.
If the item is already on its least efficient choice (ThisIndex == Least Efficient Index), it will do a CEILING function to ensure that the order is fulfilled. If not, it will do a FLOOR function instead. This is because you cannot order 3.5 units of an item, so they have to be rounded either up or down.
Expenditure - This is simply Order multiplied by the Retail Price, or how much money you spend in this iteration.
Remaining - How much of the product is left unfulfilled at the end of this iteration, to be used as To Fulfill for the next iteration.
Note: If you see formulas that are of the form =IF(ThisIndex, [calculations_here],), that is simply a check to nullify that calculation if ThisIndex is invalid.
Copy the iterations as many times as you want to the right. Something nice to do is to force the iterations to do a CEILING on the very last one to ensure that you never under-buy.
Generate a user-readable string for the purchase suggestion. You can see this on the Suggested Purchase column.
Calculate the Gallons Bought with a simple SUMPRODUCT over all the iterations.
Calculate the total expenditure with a simple SUM over all the iterations.
I hope this is what you were looking for. Regardless, it's at least a fun exercise on how much you can abuse Sheets. ;)
I'll explain an example of the situation before I ask the question.
If I have a pile of 5 numbered boxes and I scan them into a spreadsheet in the following order. 4,2,3,5,1
I copy that list into another program which adds more info to each number (which is what I want) but messes up the order. So now it is 3A,4D,1C,2B,5E.
Is there a formula I can use to reorder my new list to the original? I want to keep the original order as I print labels for these boxes and this would keep the order, meaning ordering both numerically won't work.
Thanks,
Graeme
I'd recommend an HLookup. Look for the character in your original list and add "*" which is a wild card for the second character.
Assumptions:
The first character is unique in the set.
Each value is in its own cell.
The original list is retained after intermediate program runs.
I have a situation and it goes like this:
I need to print out coordinates like the one's used in a maths graph. So (0,0) (0,1) (0,2) and so on. So if the length is specified as 10 and breadth is specified as 20 then the graph region will be all the points from (0,0) till (10,20).
I wish to store these values in a table so that these can be printed out in order.
Later on, there is a scenario that some of these values will get removed so suppose the values removed are (4,5) (4,6) (4,7) and then the main table that was created earlier should not contain these values. And I need to be able to print out the new table with the remaining values.
Till now I have only done the coding to ask for the length and the breadth values.
How should I go ahead with the rest of this?
In case you need any clarification or the question if too confusing then please leave a comment and I will try to make it better.
Any help will be very highly appreciated.
Thank you
There are a few ways of doing this depending on what you want.
The easy way is to use an array of arrays like this:
a = Array.new(11) {Array.new(21) {0}}
This creates an array like a[0][0] to a[10][20], with every item initialized to 0.
To remove an item, set it to nil:
a[4][5] = nil
When you print the array, skip any nil values:
for x in 0..10
for y in 0..20
next if a[x][y]==nil
puts a[x][y]
end
end
If your graph is very large, read about a "sparse matrix" which is how tools like Excel store many cells using less RAM for blank cells:
http://en.wikipedia.org/wiki/Sparse_matrix