PHPMaster.com has posted the third part of their "Data Structures for PHP Devs" series today, this time focusing on heaps. Heaps are a method for organizing a parent/child relationship that makes it easier to work with.
In past couple articles I've introduced you to three basic data structures: stack, queue, and tree. In this article I'll introduce you to another abstract data type that is closely related: heap. Heaps are specialized tree-like data structures which satisfy the heap property - the node value (key) of any parent is always ordered with respect to its child node values across the entire tree.
He starts off by explaining what the different types of heaps are - maxheap, minheap and (a special instance) a Priority Queue. He talks about the operations available to heaps and starts off with a binary maxheap implementation using arrays. He also mentions some of the functionality that the SPL already provides for this sort of thing - SplMaxHeap, SplMinHeap and the SplPriorityQueue.