[2346] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2006 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_ELEVATOR_H |
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| 20 | #define LEMON_ELEVATOR_H |
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| 21 | |
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| 22 | ///\ingroup auxdat |
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| 23 | ///\file |
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| 24 | ///\brief Elevator class |
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| 25 | /// |
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| 26 | ///Elevator class implements an efficient data structure |
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| 27 | ///for labeling items in push-relabel type algorithms. |
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| 28 | /// |
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| 29 | |
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| 30 | #include <test/test_tools.h> |
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| 31 | namespace lemon { |
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| 32 | |
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[2347] | 33 | ///Class for handling "labels" in push-relabel type algorithms. |
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[2346] | 34 | |
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[2347] | 35 | ///A class for handling "labels" in push-relabel type algorithms. |
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[2346] | 36 | /// |
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| 37 | ///\ingroup auxdat |
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| 38 | ///Using this class you can assign "labels" (nonnegativ integer numbers) |
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| 39 | ///to the edges or nodes of a graph, manipulate and query them through |
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| 40 | ///operations typically arising in "push-relabel" type algorithms. |
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| 41 | /// |
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| 42 | ///Each item is either \em active or not, and you can also choose a |
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| 43 | ///highest level active item. |
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| 44 | /// |
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| 45 | ///\param Graph the underlying graph type |
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| 46 | ///\param Item Type of the items the data is assigned to (Graph::Node, |
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| 47 | ///Graph::Edge, Graph::UEdge) |
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| 48 | template<class Graph, class Item> |
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| 49 | class Elevator |
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| 50 | { |
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| 51 | public: |
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| 52 | typedef typename std::vector<Item>::iterator Vit; |
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| 53 | typedef DefaultMap<Graph,Item,Vit> VitMap; |
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| 54 | typedef DefaultMap<Graph,Item,int> IntMap; |
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| 55 | |
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| 56 | const Graph &_g; |
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| 57 | int _max_level; |
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| 58 | int _item_num; |
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| 59 | VitMap _where; |
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| 60 | IntMap _level; |
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| 61 | std::vector<Item> _items; |
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| 62 | std::vector<Vit> _first; |
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| 63 | std::vector<Vit> _last_active; |
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| 64 | |
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| 65 | int _highest_active; |
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| 66 | |
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| 67 | void copy(Item i, Vit p) |
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| 68 | { |
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| 69 | _where[*p=i]=p; |
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| 70 | } |
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| 71 | void copy(Vit s, Vit p) |
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| 72 | { |
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| 73 | if(s!=p) |
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| 74 | { |
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| 75 | Item i=*s; |
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| 76 | *p=i; |
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| 77 | _where[i]=p; |
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| 78 | } |
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| 79 | } |
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| 80 | void swap(Vit i, Vit j) |
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| 81 | { |
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| 82 | Item ti=*i; |
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| 83 | Vit ct = _where[ti]; |
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| 84 | _where[ti]=_where[*i=*j]; |
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| 85 | _where[*j]=ct; |
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| 86 | *j=ti; |
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| 87 | } |
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| 88 | |
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| 89 | void checkDs() |
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| 90 | { |
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| 91 | for(typename ItemSetTraits<Graph,Item>::ItemIt i(_g);i!=INVALID;++i) |
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| 92 | { |
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| 93 | Vit w=_where[i]; |
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| 94 | int l=_level[i]; |
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| 95 | check(*w==i,"GEBASZ: CORRUPT DS"); |
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| 96 | check(_first[l]<=w,"GEBASZ: CORRUPT DS"); |
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| 97 | check(_first[l+1]>w,"GEBASZ: CORRUPT DS"); |
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| 98 | } |
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| 99 | check(_highest_active<0 || |
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| 100 | _first[_highest_active]<=_last_active[_highest_active], |
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| 101 | "GEBASZ: CORRUPT DS"); |
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| 102 | } |
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| 103 | |
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| 104 | public: |
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| 105 | ///Constructor with given maximum level. |
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| 106 | |
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| 107 | ///Constructor with given maximum level. |
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| 108 | /// |
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| 109 | ///\param g The underlying graph |
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| 110 | ///\param max_level Set the range of the possible labels to |
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| 111 | ///[0...\c max_level] |
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| 112 | Elevator(const Graph &g,int max_level) : |
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| 113 | _g(g), |
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| 114 | _max_level(max_level), |
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| 115 | _item_num(_max_level), |
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| 116 | _where(g), |
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| 117 | _level(g,0), |
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| 118 | _items(_max_level), |
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| 119 | _first(_max_level+2), |
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| 120 | _last_active(_max_level+2), |
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| 121 | _highest_active(-1) {} |
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| 122 | ///Constructor. |
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| 123 | |
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| 124 | ///Constructor. |
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| 125 | /// |
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| 126 | ///\param g The underlying graph |
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| 127 | ///The range of the possible labels is [0...\c max_level], |
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| 128 | ///where \c max_level is equal to the number of labeled items in the graph. |
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| 129 | Elevator(const Graph &g) : |
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| 130 | _g(g), |
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| 131 | _max_level(countItems<Graph, Item>(g)), |
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| 132 | _item_num(_max_level), |
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| 133 | _where(g), |
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| 134 | _level(g,0), |
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| 135 | _items(_max_level), |
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| 136 | _first(_max_level+2), |
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| 137 | _last_active(_max_level+2), |
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| 138 | _highest_active(-1) |
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| 139 | { |
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| 140 | } |
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| 141 | |
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| 142 | ///Activate item \c i. |
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| 143 | void activate(Item i) |
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| 144 | { |
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| 145 | const int l=_level[i]; |
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| 146 | swap(_where[i],++_last_active[l]); |
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| 147 | if(l>_highest_active) _highest_active=l; |
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| 148 | } |
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| 149 | |
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| 150 | ///Deactivate item \c i. |
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| 151 | void deactivate(Item i) |
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| 152 | { |
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| 153 | swap(_where[i],_last_active[_level[i]]--); |
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| 154 | _last_active[_level[i]]--; |
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| 155 | while(_highest_active>=0 && |
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| 156 | _last_active[_highest_active]<_first[_highest_active]) |
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| 157 | _highest_active--; |
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| 158 | } |
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| 159 | |
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| 160 | ///Query whether item \c i is active |
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| 161 | bool active(Item i) const { return _where[i]<=_last_active[_level[i]]; } |
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| 162 | |
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| 163 | ///Return the level of item \c i. |
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| 164 | int operator[](Item i) const { return _level[i]; } |
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| 165 | |
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| 166 | ///Returns an active item on level \c l. |
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| 167 | |
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| 168 | ///Returns an active item on level \c l. |
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| 169 | /// |
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| 170 | ///Returns an active item on level \c l or \ref INVALID if there is no such |
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| 171 | ///an item. (\c l must be from the range [0...\c max_level]. |
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| 172 | Item operator[](int l) const |
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| 173 | { |
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| 174 | return _last_active[l]>=_first[l]?*_last_active[l]:INVALID; |
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| 175 | } |
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| 176 | |
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| 177 | ///Return the number of items on level \c l. |
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| 178 | int &onLevel(int l) |
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| 179 | { |
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| 180 | return _first[l+1]-_first[l]; |
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| 181 | } |
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| 182 | ///Return the number of active items on level \c l. |
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| 183 | int &activesOnLevel(int l) |
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| 184 | { |
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| 185 | return _last_active[l]-_first[l]+1; |
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| 186 | } |
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| 187 | ///Return the maximum allowed level. |
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| 188 | int maxLevel() const |
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| 189 | { |
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| 190 | return _max_level; |
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| 191 | } |
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| 192 | |
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| 193 | ///\name Highest Active Item |
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| 194 | ///Functions for working with the highest level |
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| 195 | ///active item. |
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| 196 | |
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| 197 | ///@{ |
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| 198 | |
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| 199 | ///Return a highest level active item. |
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| 200 | |
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| 201 | ///Return a highest level active item. |
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| 202 | /// |
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| 203 | ///\return the highest level active item or INVALID if there is no active |
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| 204 | ///item. |
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| 205 | Item highestActive() const |
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| 206 | { |
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| 207 | return _highest_active>=0?*_last_active[_highest_active]:INVALID; |
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| 208 | } |
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| 209 | |
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| 210 | ///Return a highest active level. |
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| 211 | |
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| 212 | ///Return a highest active level. |
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| 213 | /// |
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| 214 | ///\return the level of the highest active item or -1 if there is no active |
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| 215 | ///item. |
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| 216 | Item highestActiveLevel() const |
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| 217 | { |
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| 218 | return _highest_active; |
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| 219 | } |
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| 220 | |
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| 221 | ///Lift the highest active item by one. |
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| 222 | |
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| 223 | ///Lift the item returned by highestActive() by one. |
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| 224 | /// |
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| 225 | void liftHighestActive() |
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| 226 | { |
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| 227 | ++_level[*_last_active[_highest_active]]; |
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| 228 | swap(_last_active[_highest_active]--,_last_active[_highest_active+1]); |
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| 229 | --_first[++_highest_active]; |
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| 230 | } |
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| 231 | |
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| 232 | ///Lift the highest active item. |
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| 233 | |
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| 234 | ///Lift the item returned by highestActive() to level \c new_level. |
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| 235 | /// |
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| 236 | /// |
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| 237 | void liftHighestActiveTo(int new_level) |
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| 238 | { |
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| 239 | const Item li = *_last_active[_highest_active]; |
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| 240 | |
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| 241 | copy(--_first[_highest_active+1],_last_active[_highest_active]--); |
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| 242 | for(int l=_highest_active+1;l<new_level;l++) |
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| 243 | { |
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| 244 | copy(--_first[l+1],_first[l]); |
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| 245 | --_last_active[l]; |
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| 246 | } |
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| 247 | copy(li,_first[new_level]); |
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| 248 | _level[li]=new_level; |
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| 249 | _highest_active=new_level; |
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| 250 | } |
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| 251 | |
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| 252 | ///@} |
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| 253 | |
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| 254 | private: |
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| 255 | int _init_lev; |
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| 256 | Vit _init_num; |
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| 257 | |
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| 258 | public: |
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| 259 | |
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| 260 | ///\name Initialization |
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| 261 | ///Using this function you can initialize the levels of the item. |
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| 262 | ///\n |
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| 263 | ///This initializatios is started with calling \c initStart(). |
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| 264 | ///Then the |
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| 265 | ///items should be listed levels by levels statring with the lowest one |
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| 266 | ///(with level 0). This is done by using \c initAddItem() |
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| 267 | ///and \c initNewLevel(). Finally \c initFinish() must be called. |
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| 268 | ///The items not listes will be put on the highest level. |
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| 269 | ///@{ |
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| 270 | |
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| 271 | ///Starts the initialization process. |
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| 272 | |
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| 273 | void initStart() |
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| 274 | { |
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| 275 | _init_lev=0; |
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| 276 | _init_num=_items.begin(); |
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| 277 | _first[0]=_items.begin(); |
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| 278 | _last_active[0]=_items.begin()-1; |
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| 279 | Vit n=_items.begin(); |
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| 280 | for(typename ItemSetTraits<Graph,Item>::ItemIt i(_g);i!=INVALID;++i) |
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| 281 | { |
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| 282 | *n=i; |
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| 283 | _where[i]=n; |
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| 284 | _level[i]=_max_level; |
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| 285 | ++n; |
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| 286 | } |
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| 287 | } |
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| 288 | |
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| 289 | ///Add an item to the current level. |
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| 290 | |
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| 291 | void initAddItem(Item i) |
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| 292 | { |
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| 293 | swap(_where[i],_init_num); |
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| 294 | _level[i]=_init_lev; |
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| 295 | ++_init_num; |
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| 296 | } |
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| 297 | |
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| 298 | ///Start a new level. |
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| 299 | |
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| 300 | ///Start a new level. |
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| 301 | ///It shouldn't be used before the items on level 0 are listed. |
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| 302 | void initNewLevel() |
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| 303 | { |
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| 304 | _init_lev++; |
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| 305 | _first[_init_lev]=_init_num; |
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| 306 | _last_active[_init_lev]=_init_num-1; |
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| 307 | } |
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| 308 | |
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| 309 | ///Finalizes the initialization process. |
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| 310 | |
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| 311 | void initFinish() |
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| 312 | { |
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| 313 | for(_init_lev++;_init_lev<=_max_level;_init_lev++) |
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| 314 | { |
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| 315 | _first[_init_lev]=_init_num; |
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| 316 | _last_active[_init_lev]=_init_num-1; |
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| 317 | } |
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| 318 | _first[_max_level+1]=_items.begin()+_item_num; |
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| 319 | _last_active[_max_level+1]=_items.begin()+_item_num-1; |
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| 320 | } |
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| 321 | |
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| 322 | ///@} |
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| 323 | |
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| 324 | }; |
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| 325 | |
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| 326 | } //END OF NAMESPACE LEMON |
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| 327 | |
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| 328 | #endif |
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| 329 | |
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