How does Google Maps explore nearby locations first?
Why does BFS always find the nearest nodes before going deeper?

The answer lies in Breadth First Search (BFS) — one of the most important graph traversal algorithms in Data Structures & Algorithms.

In today’s video, we implemented BFS completely from scratch in Java, without using any built-in Queue, List, or Graph libraries.
Everything is built manually, exactly the way coding interviews and real engineering logic expect.

WHAT WE IMPLEMENTED STEP BY STEP:
* Quick intro: What is BFS and how it works
* Why Queue is mandatory for BFS traversal
* Why Circular Queue is the best practice (performance + memory logic)
* Creating a Node class to manage graph vertices
* Implementing Queue from scratch:
1. isEmpty()
2. enqueue()
3. dequeue()
* Building Graph using Adjacency List (Undirected Graph)
* Creating BFS traversal method
* Understanding how BFS visits nodes level by level
* Dry run explanation with traversal flow
* Running the program and verifying output

In interviews, companies don’t ask:
“What is BFS?”

They ask:
* Why BFS uses a Queue and not a Stack
* Why BFS guarantees shortest path in unweighted graphs
* How to implement BFS without built-in data structures

This video answers all of that with clean Java code and logic-first explanation.

PERFECT BEFORE MOVING TO:
* Shortest Path Algorithms
* DFS Implementation
* Connected Components
* Cycle Detection
* Graph Problems in FAANG Interviews

Subscribe The Techzeen for logic-first DSA, interview-level problem solving, and system-level coding in Hindi/Urdu — learn concepts the way real engineers do

Source Code:
https://github.com/farzeen-ali/DSA-Concepts-The-Techzeen-2025

DSA Lectures:
https://github.com/farzeen-ali/DSA-Lectures-2025-The-Techzeen

DSA Playlist 2026:
https://www.youtube.com/playlist?list=PL5OhSdfH4uDvFpMTyHurVoyCsW85PVS_C

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https://www.youtube.com/playlist?list=PL5OhSdfH4uDsyUM02ZHl2mOYBpihCYsml

OOP with Java:
https://www.youtube.com/playlist?list=PL5OhSdfH4uDuiGuQW_iARmPVq1sPLsRtZ

React Native CLI Full Course 2026 :
https://www.youtube.com/playlist?list=PL5OhSdfH4uDuUpj3fwknoUVBkT2oMXyOl

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