Prompt Title: countLeaves in java

Sure! Here's an implementation of the countLeaves method in Java:

javaCopy code
public class BinarySearchTree {
    // other methods and fields
    
    public int countLeaves() {
        return countLeaves(root);
    }

    private int countLeaves(Node node) {
        if (node == null) {
            return 0;
        } else if (node.left == null && node.right == null) {
            return 1;
        } else {
            return countLeaves(node.left) + countLeaves(node.right);
        }
    }
    
    // other methods and fields
}

The countLeaves method calls a private helper method countLeaves(Node node) to count the number of leaf nodes in the binary search tree. The helper method takes a Node object as a parameter and returns the number of leaf nodes in the subtree rooted at that node. The base case of the recursion is when the current node is null, in which case the subtree contains 0 leaf nodes. If the current node has no left or right child, then it is a leaf node and the subtree contains 1 leaf node. Otherwise, the method recursively counts the number of leaf nodes in the left and right subtrees and returns the sum. The public countLeaves method simply calls the private helper method with the root of the tree as the parameter.