1.1 Classic heap sort algorithm
First version of classic double heap sort algorithm was described in [2]. In [4,
8, 14] were shown interesting applications of classic heap sort algorithm. In the
classic version is used complete binary heap in which nodes have two descendants.
Elements without children are called leaves. Full tree means that no node may
be missed inside the tree and that all the leaves are placed starting from the left
side. During sorting, elements are arranged in nodes according to conditions