priority-queue

My priority queue declared as: std::priority_queue<*MyClass> queue; class MyClass { bool operator<( const MyClass* m ) const; } is not sorting the items in the queue. What is wrong? I would not like to implement a different (Compare) class. Answer summary: The problem is, the pointer addresses are sorted. The only way to avoid this is a class that 'compares the pointers'. Now implemented as: std::priority_queue<*MyClass, vector<*MyClass>, MyClass::CompStr > queue; class MyClass { struct CompStr { bool operator()(MyClass* m1, MyClass* m2); } } Give the que the Compare functor ptr_less. If you

This is my first time using a priority queue. I'm trying to implement Dijkstra's algorithm for school and I figured I need a min heap to do this. Right now my nodes are pointers and I want to compare their weight, but I don't think I can overload > and < with pointers? Is there a way I could accomplish this? Code this far: priority_queue<Node*, vector<Node*>, node_comparison> minHeap; And then I have a struct to compare the node's weights struct node_comparison { bool operator<( const Node* a, const Node* b ) const { return a->totalWeight < b->totalWeight; } }; However it says there are too

I'm trying to implement the dijkstra algorithm with priority queue, but I can't understand how it works. I read many guide on the web but I can't understand this algorithm at all. My question are: what is the priority for each node? I think that it is the weight of the incoming edge with minimun value, but I'm not sure. Is this true? Second question, when I extract the root of the queue, how works if this node is not adjacency with no one of the visited nodes? You should use priority queue where the vertex with the shortest distance from the starting vertex will get the highest priority.

I have created a binary heap, which represents a priority queue. It's just classical well known algorithm. This heap schedules a chronological sequence of different events ( the sort key is time ). It supports 2 operation: Insert and Remove. Each node's key of the heap is greater than or equal to each of its children. However, adding events with the same key doesn't preserve the order they were added, because each time after Remove or Insert were called, the heap-up and the heap-down procedures break the order. My question is: what should be changed in a classical algorithm to preserve the

I have a priority_queue, and I want to modify some of it's contents (the priority value), will the queue be resorted then? It depends if it resorts on push/pop (more probable, becouse you just need to "insert", not resort whole), or when accessing top or pop. I really want to change some elements in the queue. Something like that: priority_queue<int> q; int a=2,b=3,c=5; int *ca=&a, *cb=&b, cc=&c; q.push(a); q.push(b); q.push(c); //q is now {2,3,5} *ca=4; //what happens to q? // 1) {3,4,5} // 2) {4,2,5} // 3) crash priority_queue copies the values you push into it. Your assignment at the end

PriorityBlockingQueue is unbounded, but I need to bound it somehow. What is the best way to achieve that? For information, the bounded PriorityBlockingQueue will be used in a ThreadPoolExecutor . NB: By bounded I don't want to throw Exception if that happens, I want to put the object in the queue and then cut it based on its priority value. Is there any good way to do this cut thingie? I actually wouldn't subclass it. While I can't put together example code right now, I'd suggest a version of the decorator pattern. Create a new class and implement the interfaces implemented by your class of