How to Traverse a Graph using DFS
How to implement Depth First Search to explore deeply into graph networks.
Create a Visited Tracker
Unlike trees, graphs can contain cycles. If you don't track visited nodes, your algorithm will run in an infinite loop. Initialize a 'visited' Hash Set or Boolean Array.
Define the Recursive Function
Create a function that takes the 'currentNode' and the 'visited' tracker as arguments.
Mark Node as Visited
The very first line inside your recursive function must add the 'currentNode' to the 'visited' tracker.
Process the Current Node
Perform whatever action is required for this traversal (e.g., printing the node's value, adding it to a result array, or checking if it is the target destination).
Iterate Through Neighbors
Retrieve all the adjacent neighbors (connections) of the 'currentNode' from your adjacency list or matrix.
Recursively Explore Unvisited Neighbors
For each neighbor, check if it exists in the 'visited' tracker. If it has NOT been visited, recursively call your DFS function on that neighbor.
Handle Disconnected Components
If the graph has 'islands' (disconnected sections), wrap your initial DFS call in a loop that iterates over every single node in the graph, calling DFS on any node that remains unvisited.
Ready to master this completely?
Want to upskill yourself, crack your next interview, and get your dream job? Join our comprehensive course to dive deeper with high-quality video tutorials, solve interview questions, and a premium community.
- On-Demand Access to All Videos
- Detailed Notes & Practice Platform
- Certificate on Completion
