set

问题 I am having trouble using my custom set,MySet, using the basic function of union and intersecting. The program compiles without error but just returns an empty set. Anybody see where the problem is? public class MySet<E> extends TreeSet<E> { Set<E> set; public MySet(){ set = null; } public MySet(Set<E> set){ this.set = set; } public void union(Set<E> s){ set.addAll(s); } public void intersection(Set<E> s){ set.retainAll(s); } } Main method public class TestSet { public static void main(String

问题 This is an algorithmic problem. If I miss any existing function in Python that helps, please give a shout. Given a set s of n elements, we can use itertools.combinations() function in Python to find all the unique k-element subsets . Let's call the set containing all these subsets S . Notice that each such subset has k distinct elements. The problem is 2-step. First, given these k-distinct-element subsets, I want to compose (some of) them such that (a composition is simply a superset of some

问题 I have a class which uses an ISet as a collection type as below: public class Client { private ISet<Contact> _contacts = new HashedSet<Contact>(); public virtual ISet<Contact> Contacts { get { return _contacts; } } } I don't want the collection itself to be able to be modified externally. However, if I change the property's type to IEnumerable as below: public class Client { private ISet<Contact> _contacts = new HashedSet<Contact>(); public virtual IEnumerable<Contact> Contacts { get { return

问题 I have to refactor old code that looks like this (I am not a very proficient C++ coder) std::set<SomeObject>::iterator it = setobject.begin(); do { it->setProperty1ToNextValue(); it->getProperty2(); it->getProperty3(); it++ } while (it != setobject.end()); Basically I want to iterate through the elements of the set and get and set/update some of their properties. I cant use the original set since I run in the problems described in this thread the object has type qualifiers that are not

问题 Say I have a Set of Strings: Set<String> things = new HashSet<String>(); things.add("coffee cup"); things.add("smartphone"); things.add("inkjet printer"); // : // list could be quite large (100K or so, perhaps loaded from a database) // : Now I want to check if another string completely contains any of the Strings in the above set. So: "a coffee cup" - matches "android smartphone" - matches "inkjet printer for sale" - matches "laser printer" - does not match "printer" - does not match The

问题 I have a set of numbers that are in a linked list. I want to compare them to see if they are the same numbers in a set. Here is my code right now: bool set::equalset(set second) { Data *travel1, *travel2; travel1 = top; travel2 = second.topval(); //gets the top value for the second set while (travel2->next != NULL && travel1->next != NULL) { if (!in(travel2->value)) //in checks if the value is in the set return false; if (!second.in(travel1->value)) //same idea here return false; travel2 =

问题 With this code: print set(a**b for a in range(2, 5) for b in range(2, 5)) I get this answer: set([64, 256, 4, 8, 9, 16, 81, 27]) Why it isn't sorted? 回答1: Sets are not ordered collections in python or any other language for that matter. Sets are usually implemented using hash keys (hash codes). So order is probably related to how hash functions are used instead of natural order of its elements. If you need order, please do consider using a list. 回答2: Sets are by their nature unordered

问题 I have 2 lists of Stack Overflow questions, group A and group B. Both have two columns, Id and Tag. e.g: |Id |Tag | -------- | -------------------------------------------- |2 |c#,winforms,type-conversion,decimal,opacity For each question in group A, I need to find in group B all matched questions that have at least one overlapping tag the question in group A, independent of the position of tags. For example, these questions should all be matched questions: |Id |Tag |----------|---------------

问题 I'm trying to convert some hard-coded inline onclicks to be dynamically created. Here's what they look like now: (html) <ul id="search-navlist"> <li><a href="#" onclick="searchExhibitorsByAlphabet(this,'A'); return false;">A</a></li> <li><a href="#" onclick="searchExhibitorsByAlphabet(this,'B'); return false;">B</a></li> <li><a href="#" onclick="searchExhibitorsByAlphabet(this,'C'); return false;">C</a></li> .... <li><a href="#" onclick="searchExhibitorsByAlphabet(this,'Z'); return false;">Z<

问题 In the following program, I have a class A with a non-static function void add() . I want use the iterator to call add() for each element in the set, but there is a error at the last element. How can I fix it? #include <iostream> #include <set> using namespace std; class A { private: int a; public: A(int x) { a = x; } void add() {a = a + 1; } bool operator<(A x) const { return a < x.a; } }; int main() { //type of the collection typedef set<A> IntSet; //define a IntSet type collection IntSet