# Graph & BFS/DFS
Confidence: high
Last verified: 2026-05-22
Generation: human_only


## TL;DR

A graph G=(V,E) models networks. BFS (queue) finds shortest paths in unweighted graphs. DFS (stack/recursion) detects cycles, performs topological sort on DAGs. Both are O(V+E).

## Core Explanation

Adjacency list: O(V+E) space, good for sparse graphs. Adjacency matrix: O(V²) space, good for dense. BFS uses queue, level-order traversal — finds shortest path in unweighted graphs. DFS uses stack (or recursion call stack), can be used for maze solving, cycle detection (back edges), strongly connected components.

## Further Reading

- [Algorithms (4th Edition)](undefined)