Question

java: i am having a hard time understanding this concept and if so please follow the below guidelines and explain what you do for me thanks

draw a binary search tree (BST) using these values : 4, 6, 11, 22, 53, 94, 21, 53

then select one of the leaves of the bst you chose and show how the below contains algorithm goes through its execution on the bst to find the node you have selected.

the contains algorithm:

private boolean contains (AnyType x, binaryNode<AnyType> t){

if (t == null) return false;

in compareResult = x.compareTo (t.element);

if (compareResult < 0){

return contains (x, t.left); }

else if (compareResult > 0){

return contains (x, t.right); }

else {

return true; //math }

}

and then alongside on your bst drawing, trace the path contains method.

thanks!

Answer 1

Let us understand the question:

• we are given a set of values 4, 6, 11, 22, 53, 94, 21, 53
• we need to construct a binary search tree from above values
• after constructing the binary search tree, we select one of the leaf nodes of the tree
• we are given an algorithm contain, that takes input a reference to node and root of the BST
• we invoke algorithm giving selected leaf node and root of the tree as input
• we have to explain how the algorithm proceeds for these values on given tree
• after that, we need to trace the path of the contain algorithm

Now, let us do everything step by step.

here is the binary search tree:

Now, let us select 21.

Pass the root of tree and reference to node 21 to the contain algorithm, t= root of tree, x=reference to node 21.

Algorithm runs on tree as follows:

• check if t==null, evaluates to false
• compare value at x to 4, compareResult wil be more than zero
• else if part executes and algorithm is invoked on (21, right subtree of 4)
• steps 1 to 3 repeats and algorithm is invoked on (21, right subtree of 6)
• steps 1 to 3 repeats and algorithm is invoked on (21, right subtree of 11)
• steps 1 to 3 repeats, but this time value of compareResult is greater than zero, so, algorithm is invoked on (21, left subtree of 22)
• this time, value of compareResult is zero, so, else pat executes and it returns zero

Path of the algorithm is traces in red color: