From dab81d1bca034e0dc96ed52a04b56e81da85c87a Mon Sep 17 00:00:00 2001
From: Cavailles Kevin <kc.mailpro@gmail.com>
Date: Thu, 2 Apr 2020 21:37:47 +0200
Subject: [PATCH] algorithme de dijkstra + commentaires

---
 .../shortestpath/DijkstraAlgorithm.java       | 124 ++++++++++++++++--
 .../graphs/algorithm/shortestpath/Label.java  |  54 ++++++++
 .../graphs/algorithm/utils/BinaryHeap.java    |  17 +++
 .../org/insa/graphs/gui/simple/Launch.java    |  38 ++++--
 .../main/java/org/insa/graphs/model/Path.java |  22 ++--
 5 files changed, 223 insertions(+), 32 deletions(-)
 create mode 100644 be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java

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 bacb8e3..9fafe4c 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
@@ -1,17 +1,121 @@
 package org.insa.graphs.algorithm.shortestpath;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.PriorityQueue;
+
+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 {
 
-    public DijkstraAlgorithm(ShortestPathData data) {
-        super(data);
-    }
+	public DijkstraAlgorithm(ShortestPathData data) {
+		super(data);
+	}
 
-    @Override
-    protected ShortestPathSolution doRun() {
-        final ShortestPathData data = getInputData();
-        ShortestPathSolution solution = null;
-        // TODO:
-        return solution;
-    }
+	@Override
+	protected ShortestPathSolution doRun() {
+		final ShortestPathData data = getInputData();
+		Graph graph = data.getGraph();
+
+		final int nbNodes = graph.size();
+
+		// Create the heap and a static array to store the labels
+		org.insa.graphs.algorithm.utils.PriorityQueue<Label> labelsHeap = new BinaryHeap<>();
+		Label labelsList[] = new Label[nbNodes];
+		Arrays.fill(labelsList, null);
+
+		//Put the origin in the heap
+		Node origin = data.getOrigin();
+		labelsList[origin.getId()] = new Label(data.getOrigin(), 0, null);
+		labelsHeap.insert(new Label(origin, 0, null));
+
+		// Notify observers about the first event (origin processed).
+		notifyOriginProcessed(data.getOrigin());
+
+		// Initialize array of predecessors.
+		Arc[] predecessorArcs = new Arc[nbNodes];
+
+		Label current, next;
+
+		// While the heap has elements
+		while (!labelsHeap.isEmpty()) {
+			
+			// Remove the min 
+			current = labelsHeap.findMin();
+			try {
+				labelsHeap.remove(current);
+			} catch (Exception e) {
+				System.out.println("fatal error");
+			}
+			
+			current.setMark();
+
+			// Iterate over the arc of the removed element
+			for (Arc arc : graph.get(current.getCurrent().getId()).getSuccessors()) {
+				if (!data.isAllowed(arc)) {
+					continue;
+				}
+
+				next = labelsList[arc.getDestination().getId()];
+			
+				//If the destination of an arc does not exist or is not marked
+				if ( next != null && next.isMarked()) {
+					continue;
+				}
+				
+				// Either create it or check if the associated cost can be reduced
+				if (next == null) {
+					next = new Label(arc.getDestination(),current.getCost() + data.getCost(arc), arc);
+					
+					labelsList[arc.getDestination().getId()] = next;
+					labelsHeap.insert(next);
+					notifyNodeReached(arc.getDestination());
+				
+				}else{
+					if (next.getCost() > current.getCost() + data.getCost(arc)) {
+						next.setCost(current.getCost() + data.getCost(arc));
+						next.setFather(arc);
+						notifyNodeReached(arc.getDestination());
+					}
+				}
+				
+
+			}
+		}
+
+		
+		ShortestPathSolution solution = null;
+
+		//Check if the destination has been reached from the source
+		if (labelsList[data.getDestination().getId()] == null) {
+			solution = new ShortestPathSolution(data, Status.INFEASIBLE);
+		} else {
+			// The destination has been found, notify the observers.
+			notifyDestinationReached(data.getDestination());
+
+			// Create the path from the array of predecessors...
+			ArrayList<Arc> arcs = new ArrayList<>();
+			Arc arc = labelsList[data.getDestination().getId()].getFather();
+			while (arc != null) {
+				arcs.add(arc);
+				arc = labelsList[arc.getOrigin().getId()].getFather();
+			}
+
+			// Reverse the path...
+			Collections.reverse(arcs);
+
+			// Create the final solution.
+			solution = new ShortestPathSolution(data, Status.OPTIMAL, new Path(graph, arcs));
+		}
+
+		return solution;
+	}
 
 }
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
new file mode 100644
index 0000000..66308c7
--- /dev/null
+++ b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/shortestpath/Label.java
@@ -0,0 +1,54 @@
+package org.insa.graphs.algorithm.shortestpath;
+
+import org.insa.graphs.model.Arc;
+import org.insa.graphs.model.Node;
+import org.insa.graphs.model.Path;
+
+public class Label implements Comparable<Label>{
+	private Node sommetCourant;
+	private boolean marque;
+	private double cout;
+	private Arc pere;
+	
+	public Label(Node sommetCourant, double cout, Arc pere) {
+		this.sommetCourant = sommetCourant;
+		this.marque = false;
+		this.cout = cout;
+		this.pere = pere;
+	}
+	
+	public Node getCurrent() {
+		return this.sommetCourant;
+	}
+	public double getCost() {
+		return this.cout;
+	}
+	public Arc getFather() {
+		return this.pere;
+	}
+	
+	public void setMark() {
+		this.marque = true;
+	}
+	
+	public void setFather(Arc father) {
+		this.pere = father;
+	}
+	
+	public void setCost(double cost) {
+		this.cout = cost;
+	}
+	
+	public boolean isMarked() {
+		return this.marque;
+	}
+	
+	@Override 
+	public String toString() {
+		return ""+this.sommetCourant.getId();
+	}
+	@Override
+	public int compareTo(Label o) {
+		return (int) (this.getCost()-o.getCost() ) ;
+	}
+}
diff --git a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/utils/BinaryHeap.java b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/utils/BinaryHeap.java
index 78b1676..b20cbcd 100644
--- a/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/utils/BinaryHeap.java
+++ b/be-graphes-algos/src/main/java/org/insa/graphs/algorithm/utils/BinaryHeap.java
@@ -1,6 +1,10 @@
 package org.insa.graphs.algorithm.utils;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Set;
+import java.util.TreeSet;
 
 /**
  * Implements a binary heap containing elements of type E.
@@ -11,6 +15,9 @@ import java.util.ArrayList;
  * @author Mark Allen Weiss
  * @author DLB
  */
+
+
+
 public class BinaryHeap<E extends Comparable<E>> implements PriorityQueue<E> {
 
     // Number of elements in heap.
@@ -50,6 +57,7 @@ public class BinaryHeap<E extends Comparable<E>> implements PriorityQueue<E> {
         else {
             this.array.set(index, value);
         }
+       
     }
 
     /**
@@ -136,13 +144,20 @@ public class BinaryHeap<E extends Comparable<E>> implements PriorityQueue<E> {
     }
 
     @Override
+    /**
+     * Remove the element x from the array if it exists
+     * Raise ElementNotFoundException otherwise
+     */
     public void remove(E x) throws ElementNotFoundException {
+    	
+    	
     	if(this.isEmpty()){
         	throw new ElementNotFoundException(x);
         }
         
         int index = -1;
         
+        //Iterate over the array and check if the x exists
         for(int i=0; i<this.currentSize;i++) {
         	if(this.array.get(i).equals(x)) {
         		index = i;
@@ -154,8 +169,10 @@ public class BinaryHeap<E extends Comparable<E>> implements PriorityQueue<E> {
         	throw new ElementNotFoundException(x);
         }
     	
+    	//If it exists, it is replaced by the "last" element
         E lastItem = this.array.get(--this.currentSize);
         this.arraySet(index, lastItem);
+        //The switched element is then sorted
         this.percolateDown(index);
         this.percolateUp(index);
         
diff --git a/be-graphes-gui/src/main/java/org/insa/graphs/gui/simple/Launch.java b/be-graphes-gui/src/main/java/org/insa/graphs/gui/simple/Launch.java
index 7868b89..b647377 100644
--- a/be-graphes-gui/src/main/java/org/insa/graphs/gui/simple/Launch.java
+++ b/be-graphes-gui/src/main/java/org/insa/graphs/gui/simple/Launch.java
@@ -50,28 +50,38 @@ public class Launch {
         final String mapName = "/Users/Kevin/Desktop/programmation/java_files/Maps/europe/france/insa.mapgr";
         final String pathName = "/Users/Kevin/Desktop/programmation/java_files/Paths/path_fr31insa_rangueil_insa.path";
 
-        // Create a graph reader.
-        final GraphReader reader = new BinaryGraphReader(
-                new DataInputStream(new BufferedInputStream(new FileInputStream(mapName))));
-
         // TODO: Read the graph.
-        final Graph graph = reader.read();
+        final Graph graph; 
 
         // Create the drawing:
-        final Drawing drawing = createDrawing();
+        final Drawing drawing;
 
-        // TODO: Draw the graph on the drawing.
-        drawing.drawGraph(graph);
+
+        try (GraphReader reader = new BinaryGraphReader(new DataInputStream(
+                new BufferedInputStream(new FileInputStream(mapName))))) {
+
+            // TODO: Read the graph.
+            graph = reader.read();
+
+            // Create the drawing:
+            drawing = createDrawing();
+
+            // TODO: Draw the graph on the drawing.
+            drawing.drawGraph(graph);
+        }
 
         // TODO: Create a PathReader.
-        final PathReader pathReader = new BinaryPathReader(
-        		new DataInputStream( new BufferedInputStream(new FileInputStream(pathName))));
+        try (PathReader pathReader = new BinaryPathReader(
+        		new DataInputStream( new BufferedInputStream(new FileInputStream(pathName))))) {
 
-        // TODO: Read the path.
-        final Path path = pathReader.readPath(graph);
+        	   // TODO: Read the path.
+            final Path path = pathReader.readPath(graph);
 
-        // TODO: Draw the path.
-        drawing.drawPath(path);
+            // TODO: Draw the path.
+            drawing.drawPath(path);
+
+        }
     }
+      
 
 }
diff --git a/be-graphes-model/src/main/java/org/insa/graphs/model/Path.java b/be-graphes-model/src/main/java/org/insa/graphs/model/Path.java
index 045af0a..f0523bf 100644
--- a/be-graphes-model/src/main/java/org/insa/graphs/model/Path.java
+++ b/be-graphes-model/src/main/java/org/insa/graphs/model/Path.java
@@ -32,11 +32,7 @@ public class Path {
      */
     public static Path createFastestPathFromNodes(Graph graph, List<Node> nodes)
             throws IllegalArgumentException {
-    	
-        Arc currentArc = null;
-        List<Arc> arcs = new ArrayList<Arc>();
-        double travelTime = 9999;
-        
+    	    
         if(nodes.size() == 0) {
         	return new Path(graph);
         }
@@ -44,6 +40,11 @@ public class Path {
         	return new Path(graph, nodes.get(0) );
         }
         
+        Arc currentArc = null;
+        List<Arc> arcs = new ArrayList<Arc>();
+        double travelTime = 9999;
+        
+        //Get the arc with the minimum travel time for each node
         for(int i=0; i<nodes.size()-1;i++) {
 	    	for(Arc a : nodes.get(i).getSuccessors()) {
 	    		if(a.getMinimumTravelTime() < travelTime 
@@ -52,6 +53,7 @@ public class Path {
 	    			travelTime = a.getMinimumTravelTime();
 	    		}
 	    	}
+	    	//raise an exception if two consecutive arcs are not linked 
 	    	if(currentArc == null) {
 	    		throw new IllegalArgumentException();
 	    	}	
@@ -78,9 +80,7 @@ public class Path {
     public static Path createShortestPathFromNodes(Graph graph, List<Node> nodes)
             throws IllegalArgumentException {
     	
-        Arc currentArc = null;
-        List<Arc> arcs = new ArrayList<Arc>();
-        float distanceMin = 9999;
+       
         
         if(nodes.size() == 0) {
         	return new Path(graph);
@@ -89,6 +89,11 @@ public class Path {
         	return new Path(graph, nodes.get(0) );
         }
         
+        Arc currentArc = null;
+        List<Arc> arcs = new ArrayList<Arc>();
+        float distanceMin = 9999;
+        
+        //Get the arc with the minimal distance for each node
         for(int i=0; i<nodes.size()-1;i++) {
 	    	for(Arc a : nodes.get(i).getSuccessors()) {
 	    		if(a.getLength() < distanceMin 
@@ -97,6 +102,7 @@ public class Path {
 	    			distanceMin = a.getLength();
 	    		}	
 	    	}
+	    	//raise an exception if two consecutive arcs are not linked 
 	    	if(currentArc == null) {
 	    		throw new IllegalArgumentException();
 	    	}