BFS vs DFS
Learn when to use each pattern and make the right choice in your coding interview.
Quick Answer
Use Bfs when you need shortest path or level-order traversal
Use Dfs when you need to explore all paths or check connectivity
Side-by-Side Comparison
Bfs
Best For
Shortest path, level order, nearest neighbor
Time
O(V+E)
Space
O(V)
Dfs
Best For
Path finding, cycle detection, topological sort
Time
O(V+E)
Space
O(V) recursive stack
How to Decide
- Need shortest path in unweighted graph? → BFS
- Need to explore all possible paths? → DFS
- Level-by-level traversal? → BFS
- Detecting cycles or backtracking? → DFS
Practice Both Patterns
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