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dijkstra.cpp
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dijkstra.cpp
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#include <iostream>
#include <vector>
#include "vertex.h"
#include "graph.h"
#include "priorityqueue.h"
#include "dijkstra.h"
using namespace std;
//========================================================================//
// class constructors
//========================================================================//
ShortestPath::ShortestPath(Graph &Copy_Graph)
{
//resize path vector
PathVector.resize(Copy_Graph.VerticesNumber);
//variable that holds current vertex index thats is being modified
int CurrentNeighbourVertexPosition;
//variable that holds new calculated vertex value
int NewVertexValue;
//variable that flag if an element exists in a queue or not
bool ElementDoesNotExist ;
// variable that stores current vertex that the algorithm is working on
Vertex CurrentVertex;
// Visited vertices queue
PriorityQueue VisitedQueue;
// Unvisited Vertices queue
PriorityQueue UnvisitedQueue;
// Neighbors vertices vector
vector<Vertex> CurrentVertexNeighborsVector;
//========================================================================//
// Algorithm steps
//========================================================================//
//========================================================================//
// 01 - Initialize graph vertices values
//========================================================================//
//initialize source vertex value with 0
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[0][0],0);
//initialize vertices values
//loop Graph Vertices and initialize their values with infinity (very high value)
for(int i = 1 ; i < Copy_Graph.GraphVertexArrayList.size() ; i++)
{
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[i][0],65000);
}
//========================================================================//
// 02 - Set starting point for algorithm
//========================================================================//
//insert starting vertex(source vertex)
UnvisitedQueue.InsertQueueElement(UnvisitedQueue,Copy_Graph.GraphVertexArrayList[0][0]);
//========================================================================//
// 03 - loop until all graph vertices are visited
//========================================================================//
//while unvisited queue is not empty
while( UnvisitedQueue.QueueSize(UnvisitedQueue) != 0 )
{
//========================================================================//
// 04 - Update current values
//========================================================================//
//make top vertex in unvisited queue is the current vertex
CurrentVertex = UnvisitedQueue.TopQueueElement(UnvisitedQueue);
//get current vertex neighbors vector
CurrentVertexNeighborsVector = Copy_Graph.GetNeighborVertices(Copy_Graph,CurrentVertex);
//========================================================================//
// 05 - loop current vertex neighbors
//========================================================================//
//loop Current Vertex Neighbors Vector
for(int i = 0 ; i < CurrentVertexNeighborsVector.size() ; i++)
{
//initialize flag with true
ElementDoesNotExist = true;
//update current connected vertex position in graph vector
for(int j = 0; j < Copy_Graph.GraphVertexArrayList.size() ; j++)
{
//if neighbors vector is found
if(Copy_Graph.GraphVertexArrayList[j][0].VertexName == CurrentVertexNeighborsVector[i].ConnectedVertexName)
{
//update current neighbor vertex position
CurrentNeighbourVertexPosition = j;
break;
}//end of if statement
}//end of for loop
//========================================================================//
// 06 - add vertex to unvisited queue
//========================================================================//
//loop visited queue
for (int j = 0 ; j < VisitedQueue.QueueSize(VisitedQueue) ; j++)
{
//check if already visited
if(VisitedQueue.VertexQueue[j].VertexName == Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].VertexName)
{
//if already visited flag it as exists in queue
ElementDoesNotExist = false;
break;
}//end of if statement
}//end of for loop
//if does not exist in queue
if(ElementDoesNotExist)
{
//insert current neighbor vertex
UnvisitedQueue.InsertQueueElement(UnvisitedQueue,Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0]);
}//end of if statement
//==========================================================================================//
// 07 - Update current neighbor vertex value and previous vertex if shorter rout was found
//==========================================================================================//
//calculate new vertex value
NewVertexValue = Copy_Graph.GetVertexValue(Copy_Graph,CurrentVertex) + CurrentVertexNeighborsVector[i].ConnectedVertexWeight;
//update Neighbors vertex value if new vertex value is smaller than current vertex value
if( NewVertexValue < Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].VertexValue )
{
//update current neighbor vertex value
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0],NewVertexValue);
//update current neighbor previous vertex name
Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].PreviousVertex = CurrentVertex.VertexName;
}//end of neighbor vertex check
}//end of Current Vertex Neighbors Vector loop
//========================================================================//
// 08 - Move to new vertex to explore
//========================================================================//
//add current vertex to visited queue
VisitedQueue.InsertQueueElement(VisitedQueue,CurrentVertex);
//remove current vertex from unvisited queue and add it to visited queue
UnvisitedQueue.RemoveTopQueueElement(UnvisitedQueue);
}//end of while loop
Vertex PathVertex;
//loop visited vertices
for(int i = 0 ; i < Copy_Graph.GraphVertexArrayList.size() ; i++)
{
PathVertex = Copy_Graph.GraphVertexArrayList[i][0];
//update path vector with path vertices along with distances
do
{
//insert path vertex to path vector
PathVector[i].insert(PathVector[i].begin(),PathVertex) ;
//update previous vertex value and path vertex
for (int j = 0 ; j < Copy_Graph.GraphVertexArrayList.size() ; j++)
{
if( Copy_Graph.GraphVertexArrayList[j][0].VertexName == PathVertex.PreviousVertex)
{
PathVertex = Copy_Graph.GraphVertexArrayList[j][0];
break;
}//end of if
}//end of for
}while( PathVertex.PreviousVertex != Copy_Graph.GraphVertexArrayList[0][0].PreviousVertex);
//end of while
}//end of for
}//end of ShortestPath constructor
ShortestPath::ShortestPath(Graph &Copy_Graph, Vertex &Copy_Vertex)
{
int SourceVertexIndex;
//resize path vector
PathVector.resize(Copy_Graph.VerticesNumber);
//variable that holds current vertex index thats is being modified
int CurrentNeighbourVertexPosition;
//variable that holds new calculated vertex value
int NewVertexValue;
//variable that flag if an element exists in a queue or not
bool ElementDoesNotExist ;
// variable that stores current vertex that the algorithm is working on
Vertex CurrentVertex;
// Visited vertices queue
PriorityQueue VisitedQueue;
// Unvisited Vertices queue
PriorityQueue UnvisitedQueue;
// Neighbors vertices vector
vector<Vertex> CurrentVertexNeighborsVector;
//========================================================================//
// Algorithm steps
//========================================================================//
//========================================================================//
// 01 - Initialize graph vertices values
//========================================================================//
//set source vertex
SourceVertexIndex = Copy_Graph.GetVertexPosition(Copy_Graph,Copy_Vertex);
//initialize vertices values
//loop Graph Vertices and initialize their values with infinity (very high value)
for(int i = 0 ; i < Copy_Graph.GraphVertexArrayList.size() ; i++)
{
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[i][0],65000);
}
//initialize source vertex value with 0
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[SourceVertexIndex][0],0);
//========================================================================//
// 02 - Set starting point for algorithm
//========================================================================//
//insert starting vertex(source vertex)
UnvisitedQueue.InsertQueueElement(UnvisitedQueue,Copy_Graph.GraphVertexArrayList[SourceVertexIndex][0]);
//========================================================================//
// 03 - loop until all graph vertices are visited
//========================================================================//
//while unvisited queue is not empty
while( UnvisitedQueue.QueueSize(UnvisitedQueue) != 0 )
{
//========================================================================//
// 04 - Update current values
//========================================================================//
//make top vertex in unvisited queue is the current vertex
CurrentVertex = UnvisitedQueue.TopQueueElement(UnvisitedQueue);
//get current vertex neighbors vector
CurrentVertexNeighborsVector = Copy_Graph.GetNeighborVertices(Copy_Graph,CurrentVertex);
//========================================================================//
// 05 - loop current vertex neighbors
//========================================================================//
//loop Current Vertex Neighbors Vector
for(int i = 0 ; i < CurrentVertexNeighborsVector.size() ; i++)
{
//initialize flag with true
ElementDoesNotExist = true;
//update current connected vertex position in graph vector
for(int j = 0; j < Copy_Graph.GraphVertexArrayList.size() ; j++)
{
//if neighbors vector is found
if(Copy_Graph.GraphVertexArrayList[j][0].VertexName == CurrentVertexNeighborsVector[i].ConnectedVertexName)
{
//update current neighbor vertex position
CurrentNeighbourVertexPosition = j;
break;
}//end of if statement
}//end of for loop
//========================================================================//
// 06 - add vertex to unvisited queue
//========================================================================//
//loop visited queue
for (int j = 0 ; j < VisitedQueue.QueueSize(VisitedQueue) ; j++)
{
//check if already visited
if(VisitedQueue.VertexQueue[j].VertexName == Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].VertexName)
{
//if already visited flag it as exists in queue
ElementDoesNotExist = false;
break;
}//end of if statement
}//end of for loop
//if does not exist in queue
if(ElementDoesNotExist)
{
//insert current neighbor vertex
UnvisitedQueue.InsertQueueElement(UnvisitedQueue,Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0]);
}//end of if statement
//==========================================================================================//
// 07 - Update current neighbor vertex value and previous vertex if shorter rout was found
//==========================================================================================//
//calculate new vertex value
NewVertexValue = Copy_Graph.GetVertexValue(Copy_Graph,CurrentVertex) + CurrentVertexNeighborsVector[i].ConnectedVertexWeight;
//update Neighbors vertex value if new vertex value is smaller than current vertex value
if( NewVertexValue < Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].VertexValue )
{
//update current neighbor vertex value
Copy_Graph.SetVertexValue(Copy_Graph,Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0],NewVertexValue);
//update current neighbor previous vertex name
Copy_Graph.GraphVertexArrayList[CurrentNeighbourVertexPosition][0].PreviousVertex = CurrentVertex.VertexName;
}//end of neighbor vertex check
}//end of Current Vertex Neighbors Vector loop
//========================================================================//
// 08 - Move to new vertex to explore
//========================================================================//
//add current vertex to visited queue
VisitedQueue.InsertQueueElement(VisitedQueue,CurrentVertex);
//remove current vertex from unvisited queue and add it to visited queue
UnvisitedQueue.RemoveTopQueueElement(UnvisitedQueue);
}//end of while loop
Vertex PathVertex;
//loop visited vertices
for(int i = 0 ; i < Copy_Graph.GraphVertexArrayList.size() ; i++)
{
PathVertex = Copy_Graph.GraphVertexArrayList[i][0];
//update path vector with path vertices along with distances
do
{
//insert path vertex to path vector
PathVector[i].insert(PathVector[i].begin(),PathVertex) ;
//update previous vertex value and path vertex
for (int j = 0 ; j < Copy_Graph.GraphVertexArrayList.size() ; j++)
{
if( Copy_Graph.GraphVertexArrayList[j][0].VertexName == PathVertex.PreviousVertex)
{
PathVertex = Copy_Graph.GraphVertexArrayList[j][0];
break;
}//end of if
}//end of for
}while( PathVertex.PreviousVertex != Copy_Graph.GraphVertexArrayList[SourceVertexIndex][0].PreviousVertex);
//end of while
}//end of for
}//end of ShortestPath constructor
//========================================================================//
// Vertices List
//========================================================================//
// Prototype : vector<Vertex> VerticesList(Graph &Copy_Graph);
// Description : a Method to return Vertices List in graph
// Arguments : Graph
// Return : Vertices list of type vector<Vertex>
vector<Vertex> ShortestPath::VerticesList(Graph &Copy_Graph)
{
vector<Vertex> VerticesVector;
//loop graph vectors
for(int i =0 ; i< Copy_Graph.GraphVertexArrayList.size() ; i++)
{
VerticesVector.push_back(Copy_Graph.GraphVertexArrayList[i][0]);
}//end of vector for loop
//return graph vertices vector
return VerticesVector;
}// end of QueueSize() Method
//========================================================================//
// Find Shortest Path between two vertices
//========================================================================//
// Prototype : vector<Vertex> FindShortestPath(ShortestPath &Copy_ShortestPath, Vertex Copy_Vertex1, Vertex Copy_Vertex2);
// Description : a Method to return vector containing shortest vertices path from vertex1 to vertex2
// Arguments : Graph,vertex1,vertex2
// Return : shortest path vertices vector of type vector<Vertex>
vector<Vertex> ShortestPath::FindShortestPath(ShortestPath &Copy_ShortestPath, Vertex &Copy_Vertex)
{
vector<Vertex> ShortestPathVector;
//loop path vector vectors
for(int i =0 ; i< Copy_ShortestPath.PathVector.size() ; i++)
{
//if vertex1 vector found
if( Copy_ShortestPath.PathVector[i][0].VertexName == Copy_Vertex.VertexName )
{
//loop vertices vector
for(int j =0 ; j< Copy_ShortestPath.PathVector[i].size() ; j++)
{
//copy calculated shortest path vector to local vector to return it
ShortestPathVector.push_back(Copy_ShortestPath.PathVector[i][j]);
}//end of vertices vector loop
}//end of vertex1 check
break;
}//end of vector for loop
//return shortest path vertices vector
return ShortestPathVector;
}// end of FindShortestPath() Method
//========================================================================//
// Calculate average path length
//========================================================================//
// Prototype : float CalculateAveragePathLength(ShortestPath &Copy_ShortestPath,Graph &Copy_Graph);
// Description : a Method to return graph average path length
// Arguments : ShortestPath,Graph
// Return : float average path length
float ShortestPath::CalculateAveragePathLength(ShortestPath &Copy_ShortestPath,Graph &Copy_Graph)
{
//total path distances
float PathSum = 0.0;
//loop path vector
for(int i =0 ; i< Copy_ShortestPath.PathVector.size() ; i++)
{
//accumulate path distance
PathSum += Copy_ShortestPath.PathVector[i][Copy_ShortestPath.PathVector[i].size()-1].VertexValue;
}//end of for loop
//calculate path length average
Copy_ShortestPath.AveragePathlength = PathSum / Copy_Graph.VerticesNumber;
//return average
return Copy_ShortestPath.AveragePathlength;
}//end of
//output stream of shortest path type
ostream& operator << (ostream &out, const ShortestPath &Copy_ShortestPath)
{
for(int i =0 ; i< Copy_ShortestPath.PathVector.size() ; i++)
{
for (int j = 0 ; j < Copy_ShortestPath.PathVector[i].size() ; j++)
{
out << Copy_ShortestPath.PathVector[i][j].PreviousVertex << "-" << Copy_ShortestPath.PathVector[i][j].VertexValue << "->" << Copy_ShortestPath.PathVector[i][j].VertexName << " " ;
}
out << endl;
}
return out;
}