======Graphs======

  * Nodes, Edges
  * No root node like trees
  * Edges can contain data, like strength of conection, etc.
  * Edges can have a direction, "Directed Edge"
  * "Undirected Graph", Edges with no direction
  * Graphs can loop back to the start, unlike Trees
  * "DAG" - Directed Acyclic Graph, - Graph that does not loop
  * 

====Connectivity====

Disconnected graph has one or more nodes not connected to the rest of the graph.

Edge List or 2D or 3D List

====Adjacency====

{{:adjacency_list.png?400|}}{{:adjacency_matrix.png?400|}}

====DFS====

Depth First Search

Use a Stack. 

====BFS====

Breadth First Search

Use a Queue

====Shortest Path Problem====

If the edges are **unweighted**, the shortest past is found via BFS.

====Dijkstra's Algorithm====