DSA

Graph Traversal

Learn how to visit all nodes in a graph using Breadth-First Search and Depth-First Search.

By TechCoder TeamLast updated: 2026-06-02
In a Nutshell

Learn how to visit all nodes in a graph using Breadth-First Search and Depth-First Search. This hands-on tutorial focuses on practical implementation of graph traversal concepts.

Graph Traversal

Unlike trees, graphs can have cycles, so we must keep track of visited nodes to avoid infinite loops.

1. Breadth-First Search (BFS)

BFS explores neighbors level-by-level using a Queue. It's ideal for finding the shortest path in an unweighted graph.

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2. Depth-First Search (DFS)

DFS goes as deep as possible along each branch before backtracking using Recursion or a Stack.

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Comparison: BFS vs DFS

FeatureBFSDFS
Data StructureQueue (LIFO)Stack / Recursion
Use CaseShortest Path (Unweighted)Connectivity, Cycle Detection
SpaceO(Width)O(Height)

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Quiz

Quiz

Question 1 of 2

Why is a 'visited' set necessary in graph traversal?

To save memory
To prevent infinite loops from cycles
To sort the nodes
It's optional