[159] | 1 | // -*- C++ -*- |
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[170] | 2 | |
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| 3 | //ha predecessor az elejen nem invalid, akkor hagyd csak ugy |
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| 4 | //scanned mutatja hogy jo ertek van-e benne vagy szemet |
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| 5 | |
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[159] | 6 | /* |
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| 7 | *template <Graph, T, Heap=FibHeap> |
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| 8 | * |
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| 9 | *Constructor: |
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| 10 | * |
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| 11 | *Dijkstra(Graph G, NodeIt s, Graph::EdgeMap<T> length) |
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| 12 | * |
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| 13 | * |
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| 14 | *Member functions: |
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| 15 | * |
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| 16 | *void run() |
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| 17 | * |
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| 18 | * The following function should be used after run() was already run. |
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| 19 | * |
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| 20 | *T dist(NodeIt v) : returns the distance from s to v. |
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| 21 | * It is 0 if v is not reachable from s. |
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| 22 | * |
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| 23 | *EdgeIt pred(NodeIt v) : returns the last edge |
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| 24 | * of a shortest s-v path. Returns an invalid iterator |
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| 25 | * if v=s or v is not reachable from s. |
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| 26 | * |
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| 27 | *bool reach(NodeIt v) : true iff v is reachable from s |
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| 28 | * |
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| 29 | */ |
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| 30 | |
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[170] | 31 | #ifndef DIJKSTRA_H |
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| 32 | #define DIJKSTRA_H |
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[159] | 33 | |
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| 34 | #include <fib_heap.h> |
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| 35 | |
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| 36 | namespace hugo { |
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| 37 | |
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| 38 | template <typename Graph, typename T, |
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| 39 | typename Heap=FibHeap<typename Graph::NodeIt, T, |
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| 40 | typename Graph::NodeMap<int> > > |
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| 41 | class Dijkstra{ |
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| 42 | typedef typename Graph::NodeIt NodeIt; |
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| 43 | typedef typename Graph::EdgeIt EdgeIt; |
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| 44 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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| 45 | |
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| 46 | Graph& G; |
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| 47 | NodeIt s; |
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| 48 | typename Graph::NodeMap<EdgeIt> predecessor; |
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| 49 | typename Graph::NodeMap<T> distance; |
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| 50 | typename Graph::EdgeMap<T>& length; |
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| 51 | typename Graph::NodeMap<bool> reached; |
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| 52 | |
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| 53 | public : |
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| 54 | |
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| 55 | /* |
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| 56 | The distance of the nodes is 0. |
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| 57 | */ |
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| 58 | Dijkstra(Graph& _G, NodeIt const _s, |
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| 59 | typename Graph::EdgeMap<T>& _length) : |
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| 60 | G(_G), s(_s), predecessor(G), distance(G), |
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| 61 | length(_length), reached(G, false) { } |
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| 62 | |
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| 63 | |
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| 64 | void run() { |
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| 65 | |
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| 66 | typename Graph::NodeMap<bool> scanned(G, false); |
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| 67 | typename Graph::NodeMap<int> heap_map(G,-1); |
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| 68 | |
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| 69 | Heap heap(heap_map); |
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| 70 | |
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| 71 | heap.push(s,0); |
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| 72 | reached.set(s, true); |
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| 73 | |
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| 74 | while ( !heap.empty() ) { |
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| 75 | |
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| 76 | NodeIt v=heap.top(); |
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| 77 | T oldvalue=heap.get(v); |
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[167] | 78 | heap.pop(); |
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[159] | 79 | distance.set(v, oldvalue); |
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[171] | 80 | scanned.set(v,true); |
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[167] | 81 | |
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[159] | 82 | OutEdgeIt e; |
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| 83 | for( G.getFirst(e,v); G.valid(e); G.next(e)) { |
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[160] | 84 | NodeIt w=G.bNode(e); |
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[159] | 85 | |
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| 86 | if ( !scanned.get(w) ) { |
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| 87 | if ( !reached.get(w) ) { |
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| 88 | reached.set(w,true); |
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| 89 | heap.push(w,oldvalue+length.get(e)); |
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| 90 | predecessor.set(w,e); |
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| 91 | } else if ( oldvalue+length.get(e) < heap.get(w) ) { |
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| 92 | predecessor.set(w,e); |
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| 93 | heap.decrease(w, oldvalue+length.get(e)); |
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| 94 | } |
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| 95 | } |
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| 96 | } |
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| 97 | } |
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| 98 | } |
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| 99 | |
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| 100 | |
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| 101 | T dist(NodeIt v) { |
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| 102 | return distance.get(v); |
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| 103 | } |
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| 104 | |
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| 105 | |
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| 106 | EdgeIt pred(NodeIt v) { |
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| 107 | if ( v!=s ) return predecessor.get(v); |
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| 108 | else return EdgeIt(); |
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| 109 | } |
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| 110 | |
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| 111 | |
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| 112 | bool reach(NodeIt v) { |
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| 113 | return reached.get(v); |
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| 114 | } |
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[167] | 115 | |
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[159] | 116 | }; |
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[167] | 117 | |
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[159] | 118 | } |
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| 119 | |
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| 120 | #endif |
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| 121 | |
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| 122 | |
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