Binary Tree Level Order Traversal

Binary Tree Level Order Traversal first search

Given a binary tree, return the level order traversal of its nodes’ values. (ie, from left to right, level by level).

``````For example:
Given binary tree [3,9,20,null,null,15,7],
3
/ \
9  20
/  \
15   7
return its level order traversal as:
[
[3],
[9,20],
[15,7]
]
``````

Binary Tree Level Order Traversal Solution

``````/**
* Definition for a binary tree node.
* public class TreeNode {
*     int val;
*     TreeNode left;
*     TreeNode right;
*     TreeNode(int x) { val = x; }
* }
*/
public class BinarySearchTreeLevelOrderTraversal {
public List<List<Integer>> levelOrder(TreeNode root) {
List<List<Integer>> result = new ArrayList<List<Integer>>();

if(root == null) {
return result;
}

List<Integer> tempList = new ArrayList<Integer>();

while(!queue.isEmpty()) {

List<Integer> list = new ArrayList<Integer>();

while(!queue.isEmpty()) {
TreeNode current = queue.remove();

if(current.left != null) {
}

if(current.right != null) {
}
}

if(list.size() > 0) {