Breadth-First Search (BFS) — Explore Level by Level

Shreyas Naphad
Jul 4
1 min read

While DFS goes deep, Breadth-First Search (BFS) is more social 😄. It explores neighbors level by level, like meeting everyone in your neighborhood before moving to the next.

BFS is a graph traversal algorithm that explores all nearby nodes first before going deeper.

🧠 The Core Idea

BFS uses a queue to keep track of which node to visit next. It starts at the source, visits all its neighbors, then moves on to the neighbors’ neighbors.

🛠️ How It Works

Start at a node.
Add it to a queue and mark it as visited.
While the queue isn’t empty:
- Remove the front node.
- Visit all unvisited neighbors and add them to the queue.

🎯 Real-Life Analogy

Think of spreading a message 📢. You tell all your friends, they tell their friends, and so on. The message spreads level by level.

📍 Where It's Used

Finding the shortest path in unweighted graphs
Crawling websites (like search engines do)
Social network friend suggestions
AI movement in grid-based games
Checking if a graph is connected

🔁 Example

     A
    / \
   B   C
  /     \
 D       E

BFS from A →A → B, C → D, E

✅ Final Thought

BFS is like a wave 🌊. It spreads out evenly, visiting everything close first, then moving outward.

Perfect for finding the shortest route when every path has the same cost.