how to use Dijkstra c++ code using array based version - c++

Question

I need to use (not implement) an array based version of Dijkstras algo .The task is that given a set of line segments(obstacles) and start/end points I have to find and draw the shortest path from start/end point.I have done the calculating part etc..but dont know how to use dijkstras with my code.My code is as follows
class Point
{
public:
int x;
int y;
Point()
{
}
void CopyPoint(Point p)
{
this->x=p.x;
this->y=p.y;
}
};
class NeighbourInfo
{
public:
Point x;
Point y;
double distance;
NeighbourInfo()
{
distance=0.0;
}
};
class LineSegment
{
public:
Point Point1;
Point Point2;
NeighbourInfo neighbours[100];
LineSegment()
{
}
void main()//in this I use my classes and some code to fill out the datastructure
{
int NoOfSegments=i;
for(int j=0;j<NoOfSegments;j++)
{
for(int k=0;k<NoOfSegments;k++)
{
if( SimpleIntersect(segments[j],segments[k]) )
{
segments[j].neighbours[k].distance=INFINITY;
segments[j].neighbours[k].x.CopyPoint(segments[k].Point1);
segments[j].neighbours[k].y.CopyPoint(segments[k].Point2);
cout<<"Intersect"<<endl;
cout<<segments[j].neighbours[k].distance<<endl;
}
else
{
segments[j].neighbours[k].distance=
EuclidianDistance(segments[j].Point1.x,segments[j].Point1.y,segments[k].Point2.x,segments[k ].Point2.y);
segments[j].neighbours[k].x.CopyPoint(segments[k].Point1);
segments[j].neighbours[k].y.CopyPoint(segments[k].Point2);
}
}
}
}
Now I have the distances from each segmnets to all other segments, amd using this data(in neighbourinfo) I want to use array based Dijkstras(restriction ) to trace out the shortest path from start/end points.There is more code , but have shortened the problem for the ease of the reader
Please Help!!Thanks and plz no .net lib/code as I am using core C++ only..Thanks in advance
But I need the array based version(strictly..) I am not suppose to use any other implemntation.

Answer 1

Dijkstras
This is how Dijkstra's works:
Its not a simple algorithm. So you will have to map this algorithm to your own code.
But good luck.
List<Nodes> found; // All processed nodes;
List<Nodes> front; // All nodes that have been reached (but not processed)
// This list is sorted by the cost of getting to this node.
List<Nodes> remaining; // All nodes that have not been explored.
remaining.remove(startNode);
front.add(startNode);
startNode.setCost(0); // Cost nothing to get to start.
while(!front.empty())
{
Node current = front.getFirstNode();
front.remove(current);
found.add(current);
if (current == endNode)
{ return current.cost(); // we found the end
}
List<Edge> edges = current.getEdges();
for(loop = edges.begin(); loop != edges.end(); ++loop)
{
Node dst = edge.getDst();
if (found.find(dst) != found.end())
{ continue; // If we have already processed this node ignore it.
}
// The cost to get here. Is the cost to get to the last node.
// Plus the cost to traverse the edge.
int cost = current.cost() + loop.cost();
Node f = front.find(dst);
if (f != front.end())
{
f.setCost(std::min(f.cost(), cost));
continue; // If the node is on the front line just update the cost
// Then continue with the next node.
}
// Its a new node.
// remove it from the remaining and add it to the front (setting the cost).
remaining.remove(dst);
front.add(dst);
dst.setCost(cost);
}
}