Implement graph data structures and traversal

[maheshj01]

Adds an adjacency list for a simple case for graphs like this

0 --- 1
 |    /
 |  /
 2  - - - 3

But this would fail for random numbers (WIth index out-of range error) Because we only allocate an array of length 4.(since we only have 4 nodes in the array).

5 --- 4
 |    /
 |  /
 2  - - - 3

[maheshj01]

@saurabh47 I think the solution for this issue is to create another array of length 4 that stores the values of all 4 nodes, What do you think?

[maheshj01]

I have submitted a change is that the correct way to solve this issue?

[saurabh47]

• For adjacency list we should use Hashmap data type
• For adjacency matrix we should use Array datatype

[maheshj01]

submitted the change

[saurabh47]

let me know once your changes finalize @maheshmnj

[maheshj01]

This is ready to merge @saurabh47

[maheshj01]

Also let me know if you have any topics in mind that needs to be added. I just realized the adjacency_list implementation should also implement a function to show "if path exists between two nodes."