Graphs (continued)

Dijkstra Algorithm
- Greedy because once a node is considered, it will not considered again. 
  * This contributes to its inefffective performance when negative edges are present.

Need a different algorithm --> Bellman-Ford
- Considers each vertex multiple times until all possibilities are exhausted.
- As with Dijkstra, finds the least cost to al other vertices in the graph
  * Must be reachable from source vertex.
  * Algorithm proceeds by finding costs one step further from each vertex.
    -> When a lower cost is found, that vertex's total cost is updated.
    -> To avoid cycles, must keep track of visited vertices.
    
Transitive closure - All possible paths between all vertices.
- Indirect paths between vertices are identified and noted.
- In an unweighted graph, it shows all connections between vertices,
  * where you can get to from each vertex
- In a directed graph, it can show the minimum cost from each vertex to all other vertices.