Graph.h

#ifndef GRAPH_H
#define GRAPH_H
#include <unordered_map>
#include <queue>
#include <functional>

#include "Vertex.h"
using namespace std;
class Graph
{
	unordered_map<int, Vertex> _vertices;

public:

	void addVertex(Vertex vertex)
	{
		_vertices[vertex.getId()] = vertex;
	}

	//MA #12 TODO: IMPLEMENT!
	unordered_map<Vertex, int> *computeShortestPath(Vertex *start)
	{
		//holds known distances
		unordered_map<Vertex, int> distances;

		//underlying heap
		priority_queue<Vertex, vector<Vertex>, PathWeightComparer> dijkstra_queue{};

		//reset start's path weight
		start->setPathWeight(0);

		//make sure that the starting vertex is in the graph
		if (_vertices.find(start->getId()) != _vertices.end())
		{
			//push on starting vertex
			dijkstra_queue.push(*start);

			//while queue not empty
			while (dijkstra_queue.empty() == false)
			{
				//push on outgoing edges that haven't been discovered
				Vertex top = dijkstra_queue.top();
				dijkstra_queue.pop();

				//Top of heap not known (in distances)?
				if (distances.find(top) == distances.end())
				{
					//make known

					//***Factor in getload here as well to decide time to take path
					int current_path_weight = top.getPathWeight()*top.getload();
					distances[top] = current_path_weight;

					//push on outgoing edges
					for (auto item : top.getEdges())
					{
						Vertex *next = item.first;
						int weight = item.second;
						next->setPathWeight(weight + current_path_weight);
						
						//not known?  add to heap
						if (distances.find(*next) == distances.end())
						{
							dijkstra_queue.push(*next);
						}
					}
				}
			}

			return &distances;
		}
	}
};

#endif