From 0e576e534b1ed7c110310d42b111acebc9e3da43 Mon Sep 17 00:00:00 2001
From: Clement LACAU <lacau@insa-toulouse.fr>
Date: Tue, 21 May 2024 19:08:04 +0200
Subject: [PATCH] From parentnode to parentarc

---
 .../shortestpath/DijkstraAlgorithm.java       | 37 +++++--------------
 .../graphs/algorithm/shortestpath/Label.java  |  9 +++--
 2 files changed, 14 insertions(+), 32 deletions(-)

diff --git a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java
index 93637d3..249294c 100644
--- a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java
+++ b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/DijkstraAlgorithm.java
@@ -66,7 +66,7 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
             double arc_cost = 0;
             for (Arc successorArc : x.getNode().getSuccessors()) {
                 Label successor = labels.get(successorArc.getDestination().getId());
-
+                arc_cost = Double.MAX_VALUE;
                 if (!successor.isMarked() && data.isAllowed(successorArc)) {
                     // This loop serves to get the length of the arc as
                     // we know its origin and destination
@@ -76,7 +76,7 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
                             // data.getcost(arc) returns a cost considering the mode chosen:
                             // TIME or LENGTH
                             // Similar to using getLength / getMinimumTravelTime
-                            arc_cost = data.getCost(arc);
+                            arc_cost = Math.min(data.getCost(arc), arc_cost);
                         }
                     }
                     
@@ -84,7 +84,7 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
                     if (successor.getCost() > possible_path_cost) {
                         // Mise à jour du label
                         successor.setPathCost(possible_path_cost);
-                        successor.setParentNode(x.getNode());
+                        successor.setParentArc(successorArc);
                         // Si le noeud n'a pas déjà été rajouté au tas, on le rajoute
                         // isReached permet de vérifier en complexité O(1)
                         // C'est un léger coût en mémoire pour un gain en vitesse
@@ -101,7 +101,7 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
             }
         }
 
-    if (labels.get(data.getDestination().getId()).getParentNode() == null) {
+    if (labels.get(data.getDestination().getId()).getParentArc() == null) {
         this.pathCost = 0;
         solution = new ShortestPathSolution(data, Status.INFEASIBLE);
     }
@@ -109,32 +109,13 @@ public class DijkstraAlgorithm extends ShortestPathAlgorithm {
         // Create the path ...
         ArrayList<Arc> arcs_path = new ArrayList<>();
 
+        Arc arc = labels.get(data.getDestination().getId()).getParentArc();
+
         // We will find the path using the parent nodes, from the destination to the
         // origin
-        Label current_label = labels.get(data.getDestination().getId());
-        Label parent_label = current_label;
-
-        while(current_label != null && current_label.getNode().getId() != data.getOrigin().getId())
-        {
-            // Find the label matching the parent node
-            parent_label = labels.get(current_label.getParentNode().getId());
-
-            // Knowing the parent node, get the arc between the parent and
-            // current node and add it to the path
-            if (parent_label != null) {
-                double minCost = Double.MAX_VALUE;
-                Arc minCostArc = null;
-                for (Arc arc : parent_label.getNode().getSuccessors()) {
-                    if (arc.getDestination().getId() == current_label.getNode().getId()
-                            && data.isAllowed(arc)
-                            && data.getCost(arc) < minCost) {
-                        minCost = Math.min(data.getCost(arc), minCost);
-                        minCostArc = arc;
-                    }
-                }
-                arcs_path.add(minCostArc);
-            }
-            current_label = parent_label;
+        while (arc != null && arc.getDestination().getId() != data.getOrigin().getId()) {
+            arcs_path.add(arc);
+            arc = labels.get(arc.getOrigin().getId()).getParentArc();
         }
 
         notifyDestinationReached(data.getDestination());
diff --git a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java
index bf8d6e6..460519c 100644
--- a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java
+++ b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java
@@ -1,6 +1,7 @@
 package org.insa.graphs.algorithm.shortestpath;
 
 import org.insa.graphs.model.Node;
+import org.insa.graphs.model.Arc;
 import org.insa.graphs.algorithm.AbstractInputData.Mode;
 
 public class Label implements Comparable<Label> {
@@ -8,7 +9,7 @@ public class Label implements Comparable<Label> {
   boolean marked;
   boolean reached;
   double pathCost;
-  Node parentNode;
+  Arc parentArc;
 
 
   public Label(Node node) {
@@ -16,7 +17,7 @@ public class Label implements Comparable<Label> {
     this.marked = false;
     this.marked = false;
     this.pathCost = Double.MAX_VALUE;
-    this.parentNode = null;
+    this.parentArc = null;
   }
 
   public Node getNode() { return this.node; }
@@ -26,8 +27,8 @@ public class Label implements Comparable<Label> {
   public void markReached() { this.reached = true; }
   public double getPathCost() { return this.pathCost; }
   public void setPathCost(double newCost) { this.pathCost = newCost; }
-  public Node getParentNode() { return this.parentNode; }
-  public void setParentNode(Node parentNode) { this.parentNode = parentNode; }
+  public Arc getParentArc() { return this.parentArc; }
+  public void setParentArc(Arc parentArc) { this.parentArc = parentArc; }
 
   public double getCost() {
     // function will be modified later