// THIS GOES IN YOUR MAIN CLASS TO TEST YOUR CODE:
// -----------------------------------------------
package datastructures.binarysearchtree;
public class Main {
public static void main(String[] args) {
BinarySearchTree myBST = new BinarySearchTree();
myBST.insert(47);
myBST.insert(21);
myBST.insert(76);
myBST.insert(18);
myBST.insert(27);
myBST.insert(52);
myBST.insert(82);
System.out.println("\nBreadth First Search:");
System.out.println( myBST.BFS() );
/*
EXPECTED OUTPUT:
----------------
Breadth First Search:
[47, 21, 76, 18, 27, 52, 82]
*/
}
}
// THIS CODE GOES IN YOUR BST CLASS:
// ---------------------------------
package datastructures.binarysearchtree;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
public class BinarySearchTree {
public Node root;
public static class Node {
public int value;
public Node left;
public Node right;
private Node(int value) {
this.value = value;
}
}
public boolean insert(int value) {
Node newNode = new Node(value);
if (root == null) {
root = newNode;
return true;
}
Node temp = root;
while (true) {
if (newNode.value == temp.value) return false;
if (newNode.value < temp.value) {
if (temp.left == null) {
temp.left = newNode;
return true;
}
temp = temp.left;
} else {
if (temp.right == null) {
temp.right = newNode;
return true;
}
temp = temp.right;
}
}
}
public boolean contains(int value) {
if (root == null) return false;
Node temp = root;
while (temp != null) {
if (value < temp.value) {
temp = temp.left;
} else if (value > temp.value) {
temp = temp.right;
} else {
return true;
}
}
return false;
}
public ArrayList<Integer> BFS() {
Node currentNode = root;
Queue<Node> queue = new LinkedList<>();
ArrayList<Integer> results = new ArrayList<>();
queue.add(currentNode);
while (queue.size() > 0) {
currentNode = queue.remove();
results.add(currentNode.value);
if (currentNode.left != null) {
queue.add(currentNode.left);
}
if (currentNode.right != null) {
queue.add(currentNode.right);
}
}
return results;
}
}