JAVA PROGRAM • LEVEL 17 — DATA STRUCTURES & ALGORITHMS IN JAVA
Traverse a Tree Level by Level in Java
Learn traverse a tree level by level in java with a complete, compiler-ready Java 17 example.
PROBLEM UNDERSTANDING
Input and expected output
No input required
1 2 3 4
COMPLETE JAVA 17 PROGRAM
Complete Java 17 implementation
import java.util.*;class Node{int v;Node left,right;Node(int v){this.v=v;}}class Main{public static void main(String[] args){Node root=new Node(1);root.left=new Node(2);root.right=new Node(3);root.left.left=new Node(4);Queue<Node> q=new ArrayDeque<>();q.offer(root);while(!q.isEmpty()){Node n=q.poll();System.out.print(n.v+" ");if(n.left!=null)q.offer(n.left);if(n.right!=null)q.offer(n.right);}}}CURRENT STEP
Select Start to walk through the important lines.
SELECTED LINE
No line selected
EXPECTED OUTPUT FOR THE SAMPLE
1 2 3 4
PROGRAM EXPLANATION
Algorithm and explanation
- Initialize the deterministic sample values used for traverse a tree level by level in java.
- Create the required object and apply BFS and Queue to its state or behavior.
- Print the final result and compare it with the documented sample output.
This Java 17 example demonstrates BFS and Queue through a complete, executable program. The values are intentionally small so students can trace each statement, verify the output, and then modify the example safely in the online compiler.
EFFICIENCY
Time and space complexity
O(n)
O(n)
DEBUGGING CHECKLIST
Common mistakes
Keep the class name Main and the entry method signature public static void main(String[] args) when using the online compiler.
Create an object before accessing instance members; static members can be accessed through the class name.
Java is case-sensitive, and every statement that requires a semicolon must end with one.