juniorGraph Theory
What is a Graph Data Structure?
Updated Apr 28, 2026
Short answer
A non-linear data structure consisting of vertices (nodes) and edges that connect them.
Deep explanation
Graphs are versatile structures for representing networks. A non-linear data structure consisting of vertices (nodes) and edges that connect them. Adjacency matrices are O(1) for edge lookups but O(V^2) space, while lists are more space-efficient for sparse graphs.
Real-world example
Social media networks (friends/followers).
Common mistakes
- Using an Adjacency Matrix for a very sparse graph with millions of nodes.
Follow-up questions
- Space complexity of Adjacency List?