set

问题 Could anyone explain how an unordered set works? I am also not sure how a set works. My main question is what is the efficiency of its find function. For example, what is the total big O run time of this? vector<int> theFirst; vector<int> theSecond; vector<int> theMatch; theFirst.push_back( -2147483648 ); theFirst.push_back(2); theFirst.push_back(44); theSecond.push_back(2); theSecond.push_back( -2147483648 ); theSecond.push_back( 33 ); //1) Place the contents into a unordered set that is O(m

问题 I'm wondering what the most efficient way of doing this is. I have points that I gather from 2 places. I am only interested in the points which are common to both places. My plan is to have 3 std::set<Point> . First I will add in the points from area A,into set A then points from B into set B and let set C be the intersection of both sets. However, I'm wondering if there is a better way of doing this that involves maybe less sets? Thanks 回答1: Your problem is so common that there even is a

问题 This seems so simple, but has turned out to be such a pain. On Windows 7, I can paste the below into a command prompt and have it set ProgramFiles(x32) to either %programfiles% or %programfiles(x86)% then echo what it was set to: %comspec% /c if exist "%programfiles%" (set "ProgramFiles(x32)=%programfiles%") else (set "%ProgramFiles(x32)=%programfiles(x86)%") && set Program && echo %programfiles(x32)% && pause However when putting this same command into a shortcut, I get this: What is going

问题 This question already has an answer here : thrust set difference fails to compile with calling a __host__ function from a __host__ __device__ function is not allowed (1 answer) Closed last year . I tried a simple program using thrust::set. It finds the difference of two sets. However I get compilation error. #include <thrust/set_operations.h> #include <thrust/execution_policy.h> #include <thrust/device_vector.h> int main() { thrust::device_vector<int> A1(7); thrust::device_vector<int> A2(5);

问题 How can I obtain all combinations for a list where combination size need only be static eg. if the list has 4 elements then it will only need permutations of length 4 not 3, 2 and 1. I'm guessing this will need recursion. Unique combinations would be helpful but I'd like to see it in simplest (no uniqueness?) form for my puppy power. 回答1: set s = { x1, x2, x3, x4 }; array solution; permute( i ) => if( i == 0 ) => print and return; while unused elements in set => take element from set which is

问题 I need to know how to set the state of a tableviewcell to selected via code. I tried the following: let cell:TblCell = tableView.cellForRowAtIndexPath(indexPath) as TblCell cell.selected = false; But this didn't work, even though it did not give any errors. Should this have worked? or is this done differently? 回答1: tableView.selectRowAtIndexPath(indexPath, animated: true, scrollPosition: .Middle) Instead of .Middle you can use .None so the tableView doesn't scroll to the selected cell. .Top

问题 Please first see original question: Encapsulation in JavaScript with getter and setter @Jacob Thanks Jacob! That is great information.I am not quite sure how that solution works but placing the methods into that return clause works well. Here is my working Class definition: function vehicle(thewheels, thecolour){ var colour=thecolour; var wheels=thewheels > 4 ? '4' : thewheels; return { getcolour: function() { return colour; }, setcolour: function(value) { colour = value; }, getwheels:

问题 In a poker where each player gets 5 cards from a 32 card deck, I am trying to calculate how many subsets contain exactly one pair using Mathematica. I created a deck with four suits and created subsets of all possible combinations of the cards and now I am trying to filter out all the wrong combinations using different methods to exclude the four of a kind and three of a kind and the full house. but the filter is still showing higher values than it actually is. The out put of my program is

问题 The following code is just to produce an example of the problem: public static void main(String[] args) { Collection<Integer> src = new ArrayList<Integer>(); Collection<Integer> dest = new ArrayList<Integer>(); src.add(2); src.add(7); src.add(3); src.add(2201); src.add(-21); dest.add(10); while (src.size() != 0) { for (int i : dest) { int min = Collections.min(src); dest.add(min); src.remove(min); } } } What I want to do is move everything from src to dest in a specific order. (Here, it's

问题 Here I have defined my own deleter , but not sure why isn't working . Second is there any way of not using for_each loop and just defining deleter using it at the time of set declaration makes all objects get deleted automatically when the set object goes out of scope . #include <iostream> #include <memory> #include <string> #include <set> #include <algorithm> using namespace std; class A { int i; public: A(int pi):i(pi) {} int intake() const { return i; } void show() { cout<<i<<endl; } ~A()