Breadth First Search and Depth First Search

Question

Can anybody give a link for a simple explanation on BFS and DFS with its implementation?

Answer 1

First of all, BFS and DFS are two ways to implement binary tree traversal. Breadth First means level order traversal. Depth First has three ways to implemnt -- , , .

Preorder:

a. Start with root,
b. mark it visited,
c. go to left node
d. (b) - mark it visited
e. Repeat (c) till there is not any new left node remaining
 (We are/might be at leaf node at this point,)
f. Is there any right node available? If yes, go to (a).

Level Order Traversal Time Complexity O(n)- Number of times each node is visited is 1 only, means total is n times.

Space Complexity- Best Case: Tree only left nodes, is O(1) Average Case: Perfect binary tree is example, n/2 number of nodes, O(n)