Graphs

Points to remember:

1. Breadth-first search is used to calculate the shortest path for  an unweighted graph. 
2. Dijkstra’s algorithm is used to calculate the shortest path for  a weighted graph. 
3. Dijkstra’s algorithm works when all the weights are positive. 
4. If you have negative weights, use the Bellman-Ford algorithm.

Commonly Interview Questions:

1. Implement BFS and DFS.
2. Check if a graph is a tree or not.
3. Count number of edges in a graph.
4. Find the shortest path between two vertices.