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