Dijkstra's algorithm for Single Source Shortest Path
1) greedy algorithm
2) uses edge "relaxation"
3) works in a way similar to Prim's greedy MST algorithm
4) O(|V|^2) 

can be expressed formally as follows:
GIVEN:
	graph   - arbitrary connected graph 
	sourceVertex  - is the initial beginning vertex 
	V   - is the set of all vertices in the graph theGraph (given)
	n   - number of vertices in theGraph (given)
	cost   - set of edges in theGraph (given)
WORKING ON:
	seen   - set of all "seen" vertices with permanent labels; it is the "chosen set" (what we are building)
	unseen - set of all "unseen" vertices; those yet to be processed
	dist   - set of "distances" to sourceVertex (priority queue) (what we are perfecting)

Dijkstra Algorithm (graph theGraph, vertex sourceVertex) {
  seen = {sourceVertex}    // this is the set of chosen vertices (vertices that have been used)
  unseen = V - {sourceVertex}
  dist[sourceVertex] = 0   // distance from source to source is 0 (in blue) 
			// (dist holds distances from source as we work on them)
  for i = 1 to n
       // use infinity for those where no edge exists from source
       dist[i] = cost[sourceVertex, i]  // dist should be a priority queue

  for i = 2 to n      // until all vertices have been chosen (the first vertex, the source has been done)
       choose vertex w in unseen where D[w] is min // should be a priority queue
       seen = seen + {w}
       unseen = unseen - {w}
       for each vertex v in unseen
               // update if this distance is better
               dist[v] = min(dist[v], dist[w] + cost[w, v]) // relax the effected unchosen nodes in priority queue 
}