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djikstra à verifier

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Soltane 2026-05-29 09:49:03 +02:00
parent 857b0215f4
commit 8035821299
2 changed files with 61 additions and 20 deletions
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79
be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java
View file

@ -1,8 +1,14 @@
package org.insa.graphs.algorithm.shortestpath;
import java.util.ArrayList;
import java.util.Collections;
import org.insa.graphs.algorithm.AbstractSolution.Status;
import org.insa.graphs.algorithm.utils.BinaryHeap;
import org.insa.graphs.model.Arc;
import org.insa.graphs.model.Graph;
import org.insa.graphs.model.Node;
import org.insa.graphs.model.Path;
public class DijkstraAlgorithm extends ShortestPathAlgorithm {
@ -30,29 +36,64 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
labels[node.getId()]=new Label(node);
}
BinaryHeap<Label> tas=new BinaryHeap<>();
}
// TODO: implement the Dijkstra algorithm
labels[data.getOrigin().getId()].setCoutRealise(0);
tas.insert(labels[data.getOrigin().getId()]);
while(!tas.isEmpty()){
Label labelMin=tas.deleteMin();
labelMin.setMarque();
if (labelMin.getSommetCourant().equals(data.getDestination())){
break;
}
for (Arc arc : labelMin.getSommetCourant().getSuccessors()) {
if (!data.isAllowed(arc)) continue;
Label labelSucc = labels[arc.getDestination().getId()];
if (!labelSucc.isMarque()) {
double nouveauCout = labelMin.getCoutRealise() + data.getCost(arc);
if (nouveauCout < labelSucc.getCoutRealise()) {
boolean dejaDansTas = Double.isFinite(labelSucc.getCoutRealise());
labelSucc.setCoutRealise(nouveauCout);
labelSucc.setPere(arc);
if (dejaDansTas) {
tas.remove(labelSucc);
} else {
notifyNodeReached(arc.getDestination());
}
tas.insert(labelSucc);
}
}
}
}
// Construction de la solution
if (labels[data.getDestination().getId()].getPere() == null) {
solution = new ShortestPathSolution(data, Status.INFEASIBLE);
} else {
notifyDestinationReached(data.getDestination());
ArrayList<Arc> arcs = new ArrayList<>();
Arc arc = labels[data.getDestination().getId()].getPere();
while (arc != null) {
arcs.add(arc);
arc = labels[arc.getOrigin().getId()].getPere();
}
Collections.reverse(arcs);
solution = new ShortestPathSolution(data, Status.OPTIMAL, new Path(graph, arcs));
}
// when the algorithm terminates, return the solution that has been found
return solution;
}
}

2
be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java
View file

@ -16,7 +16,7 @@ public class Label implements Comparable<Label>{
public Label(Node sommetCourant) {
this.sommetCourant=sommetCourant;
this.marque=false;
this.coutRealise=0;
this.coutRealise=Double.POSITIVE_INFINITY ;
this.pere=null;
}