combinations

问题 This question already has an answer here : How do I find all possible subsets of a set iteratively in R? (1 answer) Closed 6 years ago . So I am currently using the following code to generate my combinations: combn(x,y) But the thing is that function stores all of the possible combinations. I dont want to store them, I just want to produce them through like a loop or something. It would be way more efficient for my program. Is there a way to generate combinations through a for loop rather

问题 This question already has an answer here : How do I find all possible subsets of a set iteratively in R? (1 answer) Closed 6 years ago . So I am currently using the following code to generate my combinations: combn(x,y) But the thing is that function stores all of the possible combinations. I dont want to store them, I just want to produce them through like a loop or something. It would be way more efficient for my program. Is there a way to generate combinations through a for loop rather

问题 I have a mathematical problem in my JavaScript code. I need to divide a given number of players into 2 teams randomly so that each time – if players want to play again – the teams are formed again and they should be different until all the combinations are formed. Let's say I have 4 players, so all the combinations are as follows: [1,2],[1,3],[1,4],[2,3],[2,4],[3,4] However, because the team side doesn't count, there are only 3 different combinations: [1,2] vs [3,4] [1,3] vs [2,4] [1,4] vs [2

问题 I have an arraylist of Strings that want to have all possible combinations stored into another collection. For example: [air,bus,car] -> [air] [bus] [car] [air,bus] [air,car] [bus,air] [bus,car] [car,air] [car,bus] [air,bus,car] [air,car,bus] ... [car,bus,air] Repetitions are not important. The code right now I have is: public ArrayList<String> comb(ArrayList<String> wrds, ArrayList<String> str, int size) { ArrayList<String> s = new ArrayList<String>(); s.addAll(str); if(size != a1.size()) {

问题 I'm looking to maximise the number of stars given a certain budget and max limit on the combination... Example question: With a budget of 500 euro, visiting only the maximum allowed restaurants or less, dine and collect the most stars possible. I'm looking to write an efficient algorithm, that could potentially process 1 million Restaurant instances for up to 10 maxRestaurants ... Can anyone help attempt the problem? Note: This is not homework. I intentionally left the attempt empty as I don

问题 I'm looking to maximise the number of stars given a certain budget and max limit on the combination... Example question: With a budget of 500 euro, visiting only the maximum allowed restaurants or less, dine and collect the most stars possible. I'm looking to write an efficient algorithm, that could potentially process 1 million Restaurant instances for up to 10 maxRestaurants ... Can anyone help attempt the problem? Note: This is not homework. I intentionally left the attempt empty as I don

问题 I have this problem I was hoping people could point me in the right direction of figuring out because I dont even know where to start. Here's the setup, I have two tables in SQL Server, Table A is a summary table, Table B is a details table, so something like this: Table A ParentID Total Amount 1 100 2 587 Table B ParentID ChildID Amount 1 1 8 1 2 7 1 3 18 1 4 93 2 5 500 2 6 82 2 7 5 2 8 10 So for each ParentID, I need to come up with the combination of children whose Sums of their Amount

问题 I need to find the combinations in a list of lists. For example give the following list, List = [[1, 2], [1, 2, 3]] These should be the output, Comb = [[1,1],[1,2],[1,3],[2,1],[2,2],[2,3]] Another example: List = [[1,2],[1,2],[1,2,3]] Comb = [[1,1,1],[1,1,2],[1,1,3],[1,2,1],[1,2,2],[1,2,3]....etc] I know how to do it for a list with two sublists but it needs to work for any number of sublists. I'm new to prolog, please help. 回答1: try([],[]). try([L|Ls],[M|Ms]):- member(M,L), try(Ls,Ms). all(L

问题 My question is Matlab related. There exist a fnct named nchoosek([vector],integer). By using this function I would like to get all 2-elements combinations of the given vector. (i.e nchoosek([1:10000, 2])). This is very slow, as stated in matlab documentation. The question is : "Is there a faster way to do the same job?". Thank you for your time I really appreciate your efforts. 回答1: If it's only 2-element combinations you need, you can use NDGRID. Note that all two-element combinations up to

问题 Consider I have a data frame like this, set.seed(1) q<-100 df <- data.frame(Var1 = round(runif(q,1,50)), Var2 = round(runif(q,1,50)), Var3 = round(runif(q,1,50)), Var4 = round(runif(q,1,50))) attach(df) As you realized, q is standing for setting the length of the each columns in the dataframe. I want to make a filtering of all possible combinations of the columns. It can be anything. Let's say I am seeking for if the devision of the sums of the first two columns and the sums of the last two