Beginning Java Data Structures and Algorithms

Searching for a Minimum Key in a Binary Tree

The aim is to implement a method in Java to search for the minimum key in a binary tree.

Perform the following steps:

1. Add a method to the binary tree implementation with the following signature:

 public Optional<K> minKey()  

2. The method needs to find the minimum key in the tree and return it. If the tree is empty, it should return an empty optional.
3. Finding the minimum in a binary search tree requires us to always follow the left child node until we reach a node with no left child pointer. The following code demonstrates this:

public Optional<K> minKey() {  return Optional.ofNullable(root).map(this::minKey);}private K minKey(BinaryTreeNode<K, V> node) { return node.getLeft().map(this::minKey).orElse(node.getKey()); ...