Graph

Graph is a interlinked list of nodes ,here each nodes can have one or many connections.

Nodes/ Vertices

The data in a graph is called a node or vertices .

Edges

the connection between the nodes are called edges.

Example

a social network where people are node and edges is the connection between them , if two people are friend with each other they would have edges :)

2 kinds of graphs

• Directed Graph

  the do have a direction in the edges between the nodes example of a directed graph could be a internet and the web page links. the nodes are web pages and the links to the other webpages are the Edges.

• UnDirected Graph

  the don't have any direction in the edges between the nodes example could be a social network where people are connected and can send messages to each another. and anyone can send and receive messages.

How to represent a graph

• Adjacency List

  here each node is represented as a collection of it's neigbouring collection and the edges. a---b----c Node A: Node B Node B: Node A, Node B Node C: Node B

let unDirectedGraph = {  NodeA: ["NodeB"],  NodeB: ["NodeA", "NodeC"],  NodeC: ["NodeB"],};//can also be represented as array where nodes have number rather then having a name .let UDgraph = {    [1], //node A    [0,1],//node B    [1], // node C}

• Adjancecy Matrix

  a----b----c maybe we can put it in a adjancecy martrix . | a|b |c a | 0|1 |0 b | 1|0 |1 c | 0|1 |0 here zero means their are no edges or relationships while one means their are edges or relationships
  • this can be use to represent a directed graph
  • the matrix is always a sqaure matrix since the number of rows would be eqaul to the coulmns

let adjMat = [  [0, 1, 0],  [1, 0, 1],  [0, 1, 0],];

• Incidence Matrix

  it uses rows to represent nodes, and columns to represent the edges. we can have uneven number of rows and coumn here.