Should I use a Binary Heap?

Question

Follow up Question from: https://codereview.stackexchange.com/questions/30243/how-can-i-improve-upon-my-a-pathfinding-code/

Summary: I asked for help improving my pathfinding code (A*). A user quickly spotted that I was sorting a particular list of nodes a lot and that using IComparible to do so - Apparently very inefficient. He suggested using an OrderedBag, however, I have to code everything myself and can't use code from the internet.

The Question: So, would making a Binary Heap be the most effective way of maintaining ordered data, while still being able to add and remove data quickly. If so, does anyone have any links to point me in the right direction for creating one, and which one to create?

I've heard of a LinkedList - Good idea?

??? He suggest you use `I've tried a few ordered list implementations, but the OrderedBag class from Wintellect's PowerCollections is my favorite.`, so [PowerCollections](http://powercollections.codeplex.com/). What does it means `I have to code everything myself`? — xanatos, Aug 26 '13 at 13:43
This might be of interest: http://blog.matejzavrsnik.com/2013/03/c-implementations-of-binary-heaps/ — Matthew Watson, Aug 26 '13 at 13:57
@xanatos PowerCollections is ready-made code, no effort on my part - right? — Shivam Malhotra, Aug 26 '13 at 14:05
@ShivamMalhotra Not your code... But I'll say that `List<>` isn't your code... So isn't your `Sort()` method... — xanatos, Aug 26 '13 at 14:28

score 3 · Answer 1 · edited Dec 12 '21 at 11:50

If you are rolling your own as an exercise then yes, a heap is the correct data structure to build an efficient priority queue. Start with a binary heap because its fairly easy. You can always try a more complex heap later if you have time and inclination.

Questions recommending off site resources are off topic btw. The standard print source for simple algorithms and data structures is Introduction to Algorithms. But these days Wikipedia is a good source for pseudo code as well. (Note that the Wikipedia article shows how to build a max heap; you need a min heap. Figuring out how to build a min heap given the code for a max heap is a good exercise.)

This article also gives some good advice on use of binary heaps for A*.

score 0 · Answer 2 · answered Aug 26 '13 at 13:53

0

A LinkedList is a bad idea, especially for sorting. Try SortedDictionary instead if you don't want to use the OrderedBag

answered Aug 26 '13 at 13:53

matthijsb

909
5
12

Thanks, but SortedDictionary has the same problem. It is already made. Is it something I can make myself? – Shivam Malhotra Aug 26 '13 at 14:04

Should I use a Binary Heap?

2 Answers2