Algorithm Design Questions
Depth-first traversal algorithms for a binary tree are used to visit each node in the tree in a specific order. There are three commonly used depth-first traversal algorithms: pre-order, in-order, and post-order.
1. Pre-order traversal: In pre-order traversal, the algorithm visits the root node first, then recursively visits the left subtree, and finally recursively visits the right subtree. The order of visiting nodes is root, left, right.
2. In-order traversal: In in-order traversal, the algorithm recursively visits the left subtree first, then visits the root node, and finally recursively visits the right subtree. The order of visiting nodes is left, root, right. In a binary search tree, an in-order traversal will visit the nodes in ascending order.
3. Post-order traversal: In post-order traversal, the algorithm recursively visits the left subtree first, then visits the right subtree, and finally visits the root node. The order of visiting nodes is left, right, root.
These depth-first traversal algorithms can be implemented using recursion or using a stack data structure. They are useful for various applications such as searching, sorting, and evaluating expressions in a binary tree.