Breadth First Search and Depth First Search

Searching Algorithms

Greatest problem in Computer Science

Has lead to a lot of new ideas and data structures

Search engines before Google dawned were very slow. Search engines even took 10 minutes to search.

Why Search?

Trees were created to store data

Finding the data requires searching

Graph searching and Tree Searching algorithms that we are going to learn today are BFS and DFS.

Breadth First Searchb- branchingd - depth

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Breadth First Search 1

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Worst case performance – O(bd)Worst case space complexity - O(bd)Implemented using a queue. But you are free

to experiment with other data structures

Properties of BFS

Assignment:

Depth First Search

Depth First Searchb – branchingd - depth

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Depth First Search 1

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Depth First Search 1

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Depth First Search 1

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Depth First Search 1

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Depth First Search 1

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Depth First Search 1

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Can you guess the Time and Space complexity of the DFS?

Can you guess the Time and Space complexity of the DFS?

Yes, Time complexity of DFS is O(bd)

Worst case performance – O(bd)Worst case space complexity - O(d)Implemented using a queue. But you are free

to experiment with other data structures

Properties of DFS

Answer for Breadth First Assignment

What will you do if there is a loop in DFS? What are the data structures to use?

In order to reduce space complexity in BFS, why don’t we just delete all the nodes that are visited until the previous depth?

Are you sure you know BFS and DFS?

THANK YOU!!- Mino De Raj