Heap (data structure)

A heap is a specialized tree-based data structure that satisfies the heap property: if P is a parent node of C, then the key (the value) of P is either greater than or equal to (in a max heap) or less than or equal to (in a min heap) the key of C.

https://en.wikipedia.org/wiki/Heap_(data_structure)

http://vickyqi.com/2015/11/19/%E6%95%B0%E6%8D%AE%E7%BB%93%E6%9E%84%E7%B3%BB%E5%88%97%E2%80%94%E2%80%94%E5%A0%86/

Java PriorityQueue is a implementation of heap.
http://www.importnew.com/20169.html