source: NonGTP/Boost/boost/pending/mutable_heap.hpp @ 857

Revision 857, 2.1 KB checked in by igarcia, 19 years ago (diff)
Line 
1//
2//=======================================================================
3// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
4// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
5//
6// Distributed under the Boost Software License, Version 1.0. (See
7// accompanying file LICENSE_1_0.txt or copy at
8// http://www.boost.org/LICENSE_1_0.txt)
9//=======================================================================
10//
11#ifndef BOOST_GRAPH_DETAIL_MUTABLE_HEAP_H
12#define BOOST_GRAPH_DETAIL_MUTABLE_HEAP_H
13
14/*
15  There are a few things wrong with this set of functions.
16
17  ExternalData should be removed, it is not part of the core
18  algorithm. It can be handled inside the tree nodes.
19
20  The swap() should be replaced by assignment since its use is causing
21  the number of memory references to double.
22
23  The min_element should be replaced by a fixed length loop
24  (fixed at d for d-heaps).
25
26  The member functions of TreeNode should be changed to global
27  functions.
28
29  These functions will be replaced by those in heap_tree.h
30
31 */
32
33namespace boost {
34
35  template <class TreeNode, class Compare, class ExternalData>
36  inline TreeNode up_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
37    while (x.has_parent() && comp(x, x.parent()))
38      x.swap(x.parent(), edata);
39    return x;
40  }
41
42  template <class TreeNode, class Compare, class ExternalData>
43  inline TreeNode down_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
44    while (x.children().size() > 0) {
45      typename TreeNode::children_type::iterator
46        child_iter = std::min_element(x.children().begin(),
47                                      x.children().end(),
48                                      comp);
49      if (comp(*child_iter, x))
50        x.swap(*child_iter, edata);
51      else
52        break;
53    }
54    return x;
55  }
56
57  template <class TreeNode, class Compare, class ExternalData>
58  inline void update_heap(TreeNode x, const Compare& comp, ExternalData& edata) {
59    x = down_heap(x, comp, edata);
60    (void)up_heap(x, comp, edata);
61  }
62
63}
64#endif
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