C#•2y ago

Shifting a List(int) to become 1,2,3,4,5...

Hi, If I have a List like this: 2,3,4,5 And I would like for it to become: 1,2,3,4,4 This should be done by taking from the higher numbers in the list shifting them to the left so they come in order like above, how would I do that?

54 Replies

ACiDCA7•2y ago

is the second 4 in what you would like a typo? this doesnt look like a shift but more like you are just decreasing everything by one

OssieOP•2y ago

No, its not a typo I need to reformat the List to be from 1->2->3 etc. but if they have the same value at the end it won't be a problem The 5 in the original list, removes 1 from itself, and becomes the 1, and then there is 4 left in the end, Idk if it makes sense

canton7•2y ago

Can you share an actual example, which is correct?

OssieOP•2y ago

Not sure what you mean? That is the example I don't understand, if its not a typo, and I wan't it, why would I remove it?

canton7•2y ago

Scrap that, I can't read I still don't understand how 2,3,4,5 became 1,2,3,4,4 though

OssieOP•2y ago

2,3,4,5: 2 stays the same 3 stays the same 4 stays the same 5 lends 1 to the beginning of the list, so it becomes 4, and the begging now has a 1 1,2,3,4,4

canton7•2y ago

So you want to take the last item in a list and subtract 1 from it? And you also want to add 1 to the start of the list? Which of those two bits are you having trouble with?

OssieOP•2y ago

Its situational I wanna input N (number of items in the list) N, N, N... N amount of items in the list that needs to be sorted this way

canton7•2y ago

Can you give a full example? I don't follow what N, N, N... means

OssieOP•2y ago

4 2,4,6,8 Another example ^^ N is just a whole number

canton7•2y ago

OK, so that becomes 1,2,4,6,7? (Presumably not, because that's too simple, but you're not giving me enough information to have a better guess at what's going on...)

OssieOP•2y ago

That sohuld become 1,2,3,4,5,5

canton7•2y ago

How did 2,4,6,8 become 1,2,3,4,5,5?

OssieOP•2y ago

Thats the thing im trying to figure out

canton7•2y ago

Uh...

ACiDCA7•2y ago

what are the rules? everything above 5 get added to beginning?

OssieOP•2y ago

Its in danish, I can't explain it well

ero•2y ago

??translate en Dette er en eksempelsætning. bot dead?

OssieOP•2y ago

It wont work like that Let me try and translate it, so it makes sense Just to quickly clarify: n = whole number i = whole number a = whole number Some beavers wanna build a new damn, but they wanna sort their sticks before starting to build, they have n amount of stickpiles, the beavers have counted the piles and written it down in the order that the i'th pile has a<i> amount of sticks. The beaver engineer says it will be easier if they sort the piles so one pile has 1 stick, the next has 2, the next has 3 and so on. The beaver engineer needs help to know how many sticks that maximally can be used. Example: If the beavers have the following piles with sticks {2,5,4,3}, the beavers can move them around and get the following piles: {1,2,3,4,4}, in this example the answer would then be 1+2+3+4=10, since these are the sticks that makes up the piles that the beaver engineer have asked for. Input: 1:4 2:2 4 5 3 Output expected: 1: 10

canton7•2y ago

Right, so you want to sum all of the values in your input array, and then construct an array 1,2,3,4,... such that the sum of the second array is as large as it can be, while also being <= the sum of the input array

OssieOP•2y ago

Yes I have the following for now, but im not sure where to go from now:

int BunkerAmount = int.Parse(Console.ReadLine());
        var GreneInput = Console.ReadLine().Split(' ');
        
        List<int> GreneAmount = new List<int>();
        
        foreach (string Gren in GreneInput) {
            GreneAmount.Add(int.Parse(Gren)); //Tilføj til liste
        }
        
        GreneAmount.Sort(); // Sorter så de kommer i numerisk rækkefølge
        
        for (int i = 0; i < GreneAmount.Count; i++) {
            GreneAmount[i] = GreneAmount[i] - 1;
        }
        
        Console.WriteLine(string.Join(",", GreneAmount));

int BunkerAmount = int.Parse(Console.ReadLine());
        var GreneInput = Console.ReadLine().Split(' ');
        
        List<int> GreneAmount = new List<int>();
        
        foreach (string Gren in GreneInput) {
            GreneAmount.Add(int.Parse(Gren)); //Tilføj til liste
        }
        
        GreneAmount.Sort(); // Sorter så de kommer i numerisk rækkefølge
        
        for (int i = 0; i < GreneAmount.Count; i++) {
            GreneAmount[i] = GreneAmount[i] - 1;
        }
        
        Console.WriteLine(string.Join(",", GreneAmount));

This works for the 2,4,5,3 example, but not for the 2,4,6,8

canton7•2y ago

I think you're making this more complex than it is

OssieOP•2y ago

I might be lol

canton7•2y ago

The question talks about "sort the piles" but I think all you need to do is to put all of the sticks in single big pile, and then draw sticks from the big pile to form a pile of 1 stick, then a pile of 2 sticks, etc Until your big pile runs out of sticks

OssieOP•2y ago

So I would just add all the sticks from the original togehter, and then just start adding them until it runs out

canton7•2y ago

Yeah

OssieOP•2y ago

Or it becomes longer than the original input

ACiDCA7•2y ago

no it can get quite much longer than original input eg 1 2 9 which would be 1 2 3 4 (2) solution would be 10 again tho if i understood that correctly

OssieOP•2y ago

Is there an easy wat to sum all of the value of a list? I mean the first input

canton7•2y ago

.Sum(), or just use a loop and sum += element inside the loop

OssieOP•2y ago

error CS1061: 'List<int>' does not contain a definition for 'Sum' and no accessible extension method 'Sum' accepting a first argument of type 'List<int>' could be found (are you missing a using directive or an assembly reference?)

I'm using using System.Collections.Generic; Nvm i needed Linq Hm, it completes the first task, but it errors on someo f the other

ACiDCA7•2y ago

code + input + actual output + expected output would be helpful

OssieOP•2y ago

I don't know, its hidden Thats the thing

OssieOP•2y ago

OssieOP•2y ago

Forkert = wrong Lykkedes = completed Test data er skjult = Test data is hidden The first one in the top is the example with 2 5 4 3

ACiDCA7•2y ago

well show some code

canton7•2y ago

All we know is that some code you've written, which we can't see, is wrong

OssieOP•2y ago

        int BunkerAmount = int.Parse(Console.ReadLine());
        var GreneInput = Console.ReadLine().Split(' ');
        List<int> GreneAmount = new List<int>();
        List<int> Sorted = new List<int>();
        int TotalGreneAmount = 0;
        foreach (string Gren in GreneInput) {
            GreneAmount.Add(int.Parse(Gren));
        }
        TotalGreneAmount = GreneAmount.Sum();
        for (int i = 0; i < BunkerAmount; i ++) {
            Sorted.Add(i + 1);
            TotalGreneAmount -= i + 1;
        }
        Console.WriteLine(Sorted.Sum().ToString());

        int BunkerAmount = int.Parse(Console.ReadLine());
        var GreneInput = Console.ReadLine().Split(' ');
        List<int> GreneAmount = new List<int>();
        List<int> Sorted = new List<int>();
        int TotalGreneAmount = 0;
        foreach (string Gren in GreneInput) {
            GreneAmount.Add(int.Parse(Gren));
        }
        TotalGreneAmount = GreneAmount.Sum();
        for (int i = 0; i < BunkerAmount; i ++) {
            Sorted.Add(i + 1);
            TotalGreneAmount -= i + 1;
        }
        Console.WriteLine(Sorted.Sum().ToString());

canton7•2y ago

for (int i = 0; i < BunkerAmount; i ++) -- why stop at BunkerAmount?

OssieOP•2y ago

Since it's what it does in the example I think

canton7•2y ago

Where in the example? The question says to sort all of you sticks into piles, until you can't create any more piles

OssieOP•2y ago

1,2,3,4,4 -> 1+2+3+4 = 10 - wherei sth elast 4?

canton7•2y ago

Not to stop when you reach some arbitrary number of piles

ACiDCA7•2y ago

it cant fill the last stack so gets discarded

canton7•2y ago

You don't have enough sticks to make a pile with 5 sticks in, so you stop

OssieOP•2y ago

Oh But what would I then stop at if i < ??

canton7•2y ago

...when you can't create any more piles

ACiDCA7•2y ago

when rest of stick smaller then size of pile should be

canton7•2y ago

So if the next pile needs 5 sticks, and you have < 5 sticks in TotalGreneAmount, then you stop

OssieOP•2y ago

Not sure how I would do that

canton7•2y ago

You're not sure how to compare two numbers?

OssieOP•2y ago

No lol What should i have in my while loop

canton7•2y ago

I'm not going to tell you the answers I think if you start i at 1 rather than 0, you won't have all of those i+1's, and that'll make things easier

OssieOP•2y ago

I figured it out, thanks! And completed all tasks ty

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