Leetcode 199. Binary Tree Right Side view to see the leaf nodes----------Java

Given A binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can SE E ordered from top to bottom.

For example:
Given The following binary tree,

   1            <---/   2     3         <---\       5     4       <---

You should return [1, 3, 4] .

Using queues, hierarchy traversal, the last node of each layer.

/*** Definition for a binary tree node. * public class TreeNode {* int val; * TreeNode left; * TreeNode RI Ght * TreeNode (int x) {val = x;} }*/ Public classSolution { PublicList<integer>Rightsideview (TreeNode root) {List<Integer> list =NewArrayList (); if(Root = =NULL){            returnlist; } Queue<TreeNode> queue =NewLinkedList ();        Queue.add (root);  while(!Queue.isempty ()) {            intSize =queue.size ();  for(inti = 0; i < size; i++) {TreeNode node=Queue.poll (); if(Node.left! =NULL) {queue.add (node.left); }                if(Node.right! =NULL) {queue.add (node.right); }                if(i = = size-1) {list.add (node.val); }            }        }        returnlist; }}

Leetcode 199. Binary Tree Right Side view to see the leaf nodes----------Java