I'm writing a function that gets passed a pointer to an array of length 4. This array will contain integers 0 <= x <= 52 and I would like to construct an array of length 48 with every integer from da kine that's not in the passed in array. In python this would be # just included for specificity cards = [card for card in deck if card not...
Hi there, My head gets stucked finding an algorithm for my problem. Assume I have N Numbers (lets say 4) and I want have ALL X-Partitions (X = N/2) Example: 2-Partitions of {1,2,3,4} are: (1,2) (1,3) (1,4) (2,3) (2,4) (3,4) [Simply: all combinations] I don't have a clue how to generate these combinations. If someone of you have an i...
If I understand correctly, the __cmp__() function of an object is called in order to evaluate all objects in a collection while determining whether an object is a member, or 'in', the collection. However, this does not seem to be the case for sets: class MyObject(object): def __init__(self, data): self.data = data def _...
I am trying to create a number of restricted permutations of a list of items. Each item has a category, and I need to find combinations of items such that each combination does not have multiple items from the same category. To illustrate, here's some sample data: Name | Category ==========|========== 1. Orange | fruit 2. ...
Lets say there are two (non disjoint) sets of points (cartesian space), what is the best case complexity algorithm to perform the union of the two sets ? ...
I'm looking for a technique or algorithm that will give me a subset of integers from a given set that, when summed, most closely match a given target number. I have a music video and I want video for 248 frames. I have a set of clips of various lengths, all less than 248. I would like a subset of those that are closest to 248 when thei...
When comparing two key-value dictionary sets in C#: set A and set B, what is the best way to enumerate keys present in set A but missing from set B and vice-versa? For example: A = { 1, 2, 5 } B = { 2, 3, 5 } Comparing B with A, missing keys = { 1 } and new keys = { 3 }. Using Dictionary<...,...> objects, one can enumerating all val...
The parameters are thus: I have a table called Tasks with columns ID (primary key) and label (text). I have another table called Locations with a foreign key referencing Tasks' ID and a name for a location (text). In my code I have a set of locations. UPDATED: I need a query to return all tasks that have associated locations found with...
Having trouble finding a code page or other single byte encoding having accents in these positions: grave in xC1 acute in xC2 cedilla in xD0 ...
The question arose when answering to another SO question (there). When I iterate several times over a python set (without changing it between calls), can I assume it will always return elements in the same order? And if not, what is the rationale of changing the order ? Is it deterministic, or random? Or implementation defined? And whe...
I am looking for the solution of following algorithm with minimal time and space complexity. Given two arrays a and b, find all pairs of elements (a1,b1) such that a1 belongs to Array A and b1 belongs to Array B whose sum a1+b1 = k (any integer). I was able to come up with O(n log n) approach where we will sort one of the array say...
I have inherited a mapreduce codebase which mainly calculates the number of unique user IDs seen over time for different ads. To me it doesn't look like it is being done very efficiently, and I would like to know if anyone has any tips or suggestions on how to do this kind of calculation as efficiently as possible in mapreduce. We use H...
I'm looking for a database with good support for set operations (more specifically: unions). What I want is something that can store sets of short strings and calculate the union of such sets. For example, I want to add A, B, and C to a set, then D, and A to another and then get the cardinality of the union of those sets (4), but scale...
I have three sets: s0 = [set([16,9,2,10]), set([16,14,22,15]), set([14,7])] # true, 16 and 14 s1 = [set([16,9,2,10]), set([16,14,22,15]), set([7,8])] # false I want a function that will return True if every set in the list intersects with at least one other set in the list. Is there a built-in for this or a simple list comprehen...
Hi, I'd need a MySQL query to transform my nested sets structure into XML. (no PHP) The Problem is how to close all tags correct. My method of resolution: 1) Find leaves 2) Make a "TAG"-string (group_concat) and make it shorter with level This is running: A[01,16] B[02,03] C[...
I am looking for an efficient way to determine if a set is a subset of another set in Matlab or Mathematica. Example: Set A = [1 2 3 4] Set B = [4 3] Set C = [3 4 1] Set D = [4 3 2 1] The output should be: Set A Sets B and C belong to set A because A contains all of their elements, therefore, they can be deleted (the order of elements...
Hello, I saw somewhere that if we have a one-to-one function from sets X to Y mean that we have a onto function from Y to X. I can't understand it !! Someone can explain ?? ...
I need to create a 'container' object or class in Python, which keeps a record of other objects which I also define. One requirement of this container is that if two objects are deemed to be identical, one (either one) is removed. My first thought was to use a set([]) as the containing object, to complete this requirement. However, the...
I have two lists: List<User> collection1 = new List<User>(); List<User> collection2 = new List<User>(); 1) I have to get all items common to both of the lists using LINQ. However, the class User has a lot of properties and I just want to compare FirstName and LastName. 2) How can I get the items in collection1 but not in collection2 ...
I have two ordered lists of the same element type, each list having at most one element of each value (say ints and unique numbers), but otherwise with no restrictions (one may be a subset of the other, they may be completely disjunct, or share some elements but not others). How do I efficiently determine if A is ordering any two items ...