A graph data structure consists of a finite (and possibly mutable) set of nodes or vertices. A graph may be either undirected or directed

Graph supports add, delete, neighbors, adjacent operations. Depth-first search and breadth-first search are the methods uses to find the paths between two nodes. The graph can be represented using adjacency list, adjacency matrix and Incidence matrix. Graph useful in network analysis, travel from one city another city, chemistry or physicals, social networking sites and more.

Graph section explains how to implement the Graph and various applications related with Graph operation.

Data structure problems
159 Breathe First Search
Breadth First Search is an algorithm for searching the nodes in tree or graph data structures. It starts from the root node and explores the neighbor nodes first, before moving to the next level neighbors.
160 Depth First Search
Depth First Search algorithm is an algorithm to search node from tree or graph. DFS algorithm starts traversing from the root. It traverses each branch before backtracking.