Advertisements The docs for queue.PriorityQueue say: The lowest valued entries are retrieved first (the lowest valued entry is the one returned by sorted(list(entries))[0]). Does that mean that every time I use the get method of a PriorityQueue that the elements are re-sorted? That would seem inefficient. >Solution : That does not means that the elements… Read More Does PriorityQueue call sorted every time get is called?

Advertisements I’m trying to make a program that has a std::priority_queue of objects. I want the queue to order the objects based on A::num. This is the code: #include <iostream> #include <queue> #include <vector> class A { public: int num; A (int n) { this->num = n; } ~A() { std::cout << "Deleting an A\n";… Read More Custom ordering for std::priority_queue

Advertisements I have a class foo, and inside the class, i need a static priority queue bar that holds pointers to some number of foo objects, and the foo object also has a private member buzz that will hold the weight of the objects when compared. So far, I have tried the following: class foo{… Read More Static priority queue of pointers in c++

Advertisements When working with std::priority_queue, I tried to clear the contents of the priority queue like this: #include <iostream> #include <queue> #include <vector> using std::cout; using std::priority_queue; using std::vector; int main() { const auto comp = [](int a, int b) { return a > b; }; auto a = priority_queue<int, vector<int>, decltype(comp)>(comp); a.push(10); a.push(9); a.push(8);… Read More C++ Reuse Lambda as Compare function in `std::priority_queue`

Advertisements I would like to inherit from STL priority queue to have some additional functionality such as: allowing removal. But I am struggling to make this work when I use custom comparators. MWE: #include <queue> template<typename T, class Container=std::vector<T>, class Compare=std::less<typename Container::value_type>> class custom_priority_queue : public std::priority_queue<T, Container, Compare> { public: // My additional functions… Read More Inheritance from STL priority_queue with custom comparator not working

Advertisements How to clear a priority_queue that uses user-defined compare? From https://en.cppreference.com/w/cpp/container/priority_queue, I reduced the use of priority_queue to the case I need (= queue with user-defined compare) >> cat test.cpp #include <functional> #include <queue> #include <vector> #include <iostream> #include <utility> auto queue_cmp = [](std::pair<int, double> const& lhs, std::pair<int, double> const& rhs) { return lhs.second… Read More How to clear a `priority_queue` that uses user-defined compare?

Advertisements I would like to create a PriorityQueue to store int[]. The first element in the array is gonna be the criteria for the comparisons. I could do that easily in Java, though I could not convert it to C#. Could you please guide me? >Solution : Priority queues don’t work the same way in… Read More PriorityQueue containing array C#

Advertisements C# .Net have priorityQueue library which I used like this PriorityQueue<char, int> q = new PriorityQueue<char, int>(); q.Enqueue(‘c’, 1); q.Dequeue(); // only printc ‘c’ I looked in the ms document to find out a way to be able to print ‘c’ priority (i.e: 1) but haven’t found any. Am I missing something obvious? Thanks… Read More C# priorityQueue Dequeue return type

Advertisements I been studying priority_queue in c++ from Leetcode and I found this code from solution I understand that this is minimum heap but don’t understand how is this storing 3 elements to minHeap. is vector<int> gets matrix[r][0], vector<vector<int>> gets r and greater<> gets 0???? Why do we need to put priority_queue<int,vector<int>,greater<int>> minHeap a vector<int>… Read More How to put 3 elements in priority_queue in c++