Interview Q&A / Data Structures & Algorithms
Data Structures & Algorithms interview questions
Arrays, linked lists, hashing, trees and patterns, with line-by-line code and complexity.
Prefer rapid revision? Practise Data Structures & Algorithms short interview answers →
- What is the difference between BFS and DFS, and when would you use each?
BFS (breadth-first search) explores a graph level by level using a queue, so it finds the shortest path in an unweighted graph. DFS (depth-first search) goes as deep as possible along one path before backtracking, using a stack or recursion, and suits cycle detection, topological sort and exploring all paths. Both take O(V + E) time.
IntermediateIn-depthCoding4 min read