r853:ec0b1b423b8b
Fri, 16 Oct 2009 01:06:16
[Not Reviewed]
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@@ -48,3 +48,3 @@ |
| 48 | 48 |
/// efficient specialized version of the \ref CapacityScaling |
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/// " |
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/// "successive shortest path" algorithm directly for this problem. |
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| 50 | 50 |
/// Therefore this class provides query functions for flow values and |
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@@ -59,3 +59,3 @@ |
| 59 | 59 |
/// |
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/// \note For finding node-disjoint paths this algorithm can be used |
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/// \note For finding \e node-disjoint paths, this algorithm can be used |
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| 61 | 61 |
/// along with the \ref SplitNodes adaptor. |
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@@ -111,19 +111,12 @@ |
| 111 | 111 |
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// The digraph the algorithm runs on |
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| 113 | 112 |
const Digraph &_graph; |
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|
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// The main maps |
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const LengthMap &_length; |
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| 116 | 114 |
const FlowMap &_flow; |
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const LengthMap &_length; |
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PotentialMap &_potential; |
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// The distance map |
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PotentialMap _dist; |
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// The pred arc map |
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PotentialMap &_pi; |
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| 123 | 116 |
PredMap &_pred; |
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// The processed (i.e. permanently labeled) nodes |
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std::vector<Node> _proc_nodes; |
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| 127 | 117 |
Node _s; |
| 128 | 118 |
Node _t; |
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PotentialMap _dist; |
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std::vector<Node> _proc_nodes; |
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@@ -131,15 +124,19 @@ |
| 131 | 124 |
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/// Constructor. |
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ResidualDijkstra( const Digraph &graph, |
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const FlowMap &flow, |
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const LengthMap &length, |
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PotentialMap &potential, |
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PredMap &pred, |
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Node s, Node t ) : |
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_graph(graph), _flow(flow), _length(length), _potential(potential), |
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// Constructor |
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ResidualDijkstra(Suurballe &srb) : |
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_graph(srb._graph), _length(srb._length), |
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_flow(*srb._flow), _pi(*srb._potential), _pred(srb._pred), |
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_s(srb._s), _t(srb._t), _dist(_graph) {}
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// Run the algorithm and return true if a path is found |
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// from the source node to the target node. |
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bool run(int cnt) {
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return cnt == 0 ? startFirst() : start(); |
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} |
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| 141 | 136 |
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/// \brief Run the algorithm. It returns \c true if a path is found |
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/// from the source node to the target node. |
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private: |
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// Execute the algorithm for the first time (the flow and potential |
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// functions have to be identically zero). |
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bool startFirst() {
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| 145 | 142 |
HeapCrossRef heap_cross_ref(_graph, Heap::PRE_HEAP); |
| ... | ... |
@@ -153,6 +150,51 @@ |
| 153 | 150 |
Node u = heap.top(), v; |
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Length d = heap.prio() |
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Length d = heap.prio(), dn; |
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_dist[u] = heap.prio(); |
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_proc_nodes.push_back(u); |
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heap.pop(); |
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// Traverse outgoing arcs |
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for (OutArcIt e(_graph, u); e != INVALID; ++e) {
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v = _graph.target(e); |
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switch(heap.state(v)) {
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case Heap::PRE_HEAP: |
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heap.push(v, d + _length[e]); |
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_pred[v] = e; |
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break; |
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case Heap::IN_HEAP: |
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dn = d + _length[e]; |
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if (dn < heap[v]) {
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heap.decrease(v, dn); |
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_pred[v] = e; |
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} |
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break; |
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case Heap::POST_HEAP: |
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break; |
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} |
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} |
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} |
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if (heap.empty()) return false; |
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// Update potentials of processed nodes |
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Length t_dist = heap.prio(); |
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for (int i = 0; i < int(_proc_nodes.size()); ++i) |
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_pi[_proc_nodes[i]] = _dist[_proc_nodes[i]] - t_dist; |
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return true; |
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} |
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// Execute the algorithm. |
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bool start() {
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HeapCrossRef heap_cross_ref(_graph, Heap::PRE_HEAP); |
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Heap heap(heap_cross_ref); |
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heap.push(_s, 0); |
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_pred[_s] = INVALID; |
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_proc_nodes.clear(); |
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// Process nodes |
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while (!heap.empty() && heap.top() != _t) {
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Node u = heap.top(), v; |
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Length d = heap.prio() + _pi[u], dn; |
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_dist[u] = heap.prio(); |
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_proc_nodes.push_back(u); |
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heap.pop(); |
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| 158 | 200 |
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@@ -163,15 +205,15 @@ |
| 163 | 205 |
switch(heap.state(v)) {
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case Heap::PRE_HEAP: |
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heap.push(v, d + _length[e] - _potential[v]); |
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_pred[v] = e; |
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break; |
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case Heap::IN_HEAP: |
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nd = d + _length[e] - _potential[v]; |
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if (nd < heap[v]) {
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heap.decrease(v, nd); |
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case Heap::PRE_HEAP: |
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heap.push(v, d + _length[e] - _pi[v]); |
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_pred[v] = e; |
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} |
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break; |
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case Heap::POST_HEAP: |
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break; |
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break; |
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case Heap::IN_HEAP: |
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dn = d + _length[e] - _pi[v]; |
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if (dn < heap[v]) {
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heap.decrease(v, dn); |
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_pred[v] = e; |
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} |
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break; |
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case Heap::POST_HEAP: |
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break; |
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| 177 | 219 |
} |
| ... | ... |
@@ -185,15 +227,15 @@ |
| 185 | 227 |
switch(heap.state(v)) {
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case Heap::PRE_HEAP: |
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heap.push(v, d - _length[e] - _potential[v]); |
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_pred[v] = e; |
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break; |
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case Heap::IN_HEAP: |
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nd = d - _length[e] - _potential[v]; |
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if (nd < heap[v]) {
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heap.decrease(v, nd); |
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case Heap::PRE_HEAP: |
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heap.push(v, d - _length[e] - _pi[v]); |
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_pred[v] = e; |
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} |
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break; |
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case Heap::POST_HEAP: |
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break; |
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break; |
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case Heap::IN_HEAP: |
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dn = d - _length[e] - _pi[v]; |
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if (dn < heap[v]) {
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heap.decrease(v, dn); |
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_pred[v] = e; |
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} |
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break; |
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case Heap::POST_HEAP: |
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break; |
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| 199 | 241 |
} |
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@@ -207,3 +249,3 @@ |
| 207 | 249 |
for (int i = 0; i < int(_proc_nodes.size()); ++i) |
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_pi[_proc_nodes[i]] += _dist[_proc_nodes[i]] - t_dist; |
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return true; |
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@@ -228,8 +270,8 @@ |
| 228 | 270 |
// The source node |
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Node |
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Node _s; |
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// The target node |
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Node |
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Node _t; |
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// Container to store the found paths |
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std::vector< |
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std::vector<Path> _paths; |
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int _path_num; |
| ... | ... |
@@ -238,5 +280,2 @@ |
| 238 | 280 |
PredMap _pred; |
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// Implementation of the Dijkstra algorithm for finding augmenting |
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// shortest paths in the residual network |
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ResidualDijkstra *_dijkstra; |
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| 242 | 281 |
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@@ -260,3 +299,2 @@ |
| 260 | 299 |
if (_local_potential) delete _potential; |
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delete _dijkstra; |
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} |
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@@ -344,3 +382,3 @@ |
| 344 | 382 |
void init(const Node& s) {
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_s = s; |
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@@ -374,6 +412,4 @@ |
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int findFlow(const Node& t, int k = 2) {
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_target = t; |
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_dijkstra = |
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new ResidualDijkstra( _graph, *_flow, _length, *_potential, _pred, |
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_source, _target ); |
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_t = t; |
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ResidualDijkstra dijkstra(*this); |
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| 379 | 415 |
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@@ -383,3 +419,3 @@ |
| 383 | 419 |
// Run Dijkstra |
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if (! |
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if (!dijkstra.run(_path_num)) break; |
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++_path_num; |
| ... | ... |
@@ -387,3 +423,3 @@ |
| 387 | 423 |
// Set the flow along the found shortest path |
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Node u = |
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Node u = _t; |
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Arc e; |
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@@ -404,4 +440,4 @@ |
| 404 | 440 |
/// |
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/// This function computes the paths from the found minimum cost flow, |
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/// which is the union of some arc-disjoint paths. |
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/// This function computes arc-disjoint paths from the found minimum |
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/// cost flow, which is the union of them. |
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/// |
| ... | ... |
@@ -413,7 +449,7 @@ |
| 413 | 449 |
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paths.clear(); |
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paths.resize(_path_num); |
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_paths.clear(); |
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_paths.resize(_path_num); |
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for (int i = 0; i < _path_num; ++i) {
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Node n = _source; |
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while (n != _target) {
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Node n = _s; |
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while (n != _t) {
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OutArcIt e(_graph, n); |
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@@ -421,3 +457,3 @@ |
| 421 | 457 |
n = _graph.target(e); |
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_paths[i].addBack(e); |
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res_flow[e] = 0; |
| ... | ... |
@@ -520,3 +556,3 @@ |
| 520 | 556 |
const Path& path(int i) const {
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return |
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return _paths[i]; |
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| 522 | 558 |
} |
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