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88 lines
2.1 KiB
88 lines
2.1 KiB
// (C) Copyright Jeremy Siek 2004 |
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// Distributed under the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_DETAIL_DISJOINT_SETS_HPP |
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#define BOOST_DETAIL_DISJOINT_SETS_HPP |
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namespace boost { |
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namespace detail { |
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template <class ParentPA, class Vertex> |
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Vertex |
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find_representative_with_path_halving(ParentPA p, Vertex v) |
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{ |
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Vertex parent = get(p, v); |
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Vertex grandparent = get(p, parent); |
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while (parent != grandparent) { |
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put(p, v, grandparent); |
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v = grandparent; |
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parent = get(p, v); |
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grandparent = get(p, parent); |
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} |
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return parent; |
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} |
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template <class ParentPA, class Vertex> |
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Vertex |
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find_representative_with_full_compression(ParentPA parent, Vertex v) |
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{ |
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Vertex old = v; |
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Vertex ancestor = get(parent, v); |
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while (ancestor != v) { |
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v = ancestor; |
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ancestor = get(parent, v); |
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} |
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v = get(parent, old); |
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while (ancestor != v) { |
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put(parent, old, ancestor); |
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old = v; |
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v = get(parent, old); |
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} |
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return ancestor; |
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} |
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/* the postcondition of link sets is: |
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component_representative(i) == component_representative(j) |
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*/ |
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template <class ParentPA, class RankPA, class Vertex, |
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class ComponentRepresentative> |
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inline void |
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link_sets(ParentPA p, RankPA rank, Vertex i, Vertex j, |
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ComponentRepresentative comp_rep) |
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{ |
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i = comp_rep(p, i); |
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j = comp_rep(p, j); |
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if (i == j) return; |
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if (get(rank, i) > get(rank, j)) |
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put(p, j, i); |
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else { |
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put(p, i, j); |
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if (get(rank, i) == get(rank, j)) |
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put(rank, j, get(rank, j) + 1); |
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} |
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} |
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// normalize components has the following postcondidition: |
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// i >= p[i] |
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// that is, the representative is the node with the smallest index in its class |
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// as its precondition it it assumes that the node container is compressed |
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template <class ParentPA, class Vertex> |
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inline void |
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normalize_node(ParentPA p, Vertex i) |
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{ |
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if (i > get(p,i) || get(p, get(p,i)) != get(p,i)) |
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put(p,i, get(p, get(p,i))); |
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else { |
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put(p, get(p,i), i); |
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put(p, i, i); |
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} |
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} |
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} // namespace detail |
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} // namespace boost |
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#endif // BOOST_DETAIL_DISJOINT_SETS_HPP
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