BinaryTreeBFS.java

import java.util.*;

class TreeNode {
    int val;
    TreeNode left;
    TreeNode right;

    TreeNode(int x) {
        val = x;
    }
}

public class BinaryTreeBFS {

    public List<Integer> bfsTraversal(TreeNode root) {
        List<Integer> result = new ArrayList<>();
        if (root == null) {
            return result;
        }

        Queue<TreeNode> queue = new LinkedList<>();
        queue.offer(root);

        while (!queue.isEmpty()) {
            TreeNode node = queue.poll();
            result.add(node.val);

            if (node.left != null) {
                queue.offer(node.left);
            }
            if (node.right != null) {
                queue.offer(node.right);
            }
        }

        return result;
    }

    // Example usage:
    public static void main(String[] args) {
        BinaryTreeBFS treeBFS = new BinaryTreeBFS();

        // Creating a binary tree
        TreeNode root = new TreeNode(1);
        root.left = new TreeNode(2);
        root.right = new TreeNode(3);
        root.left.left = new TreeNode(4);
        root.left.right = new TreeNode(5);

        // Performing BFS traversal
        List<Integer> bfsResult = treeBFS.bfsTraversal(root);
        System.out.println("BFS Traversal: " + bfsResult);
    }
}